Ask ISP Owner Barry Shein About the Spam Wars

Spam sucks. But it's worse for ISPs than for the rest of us, because they get bounces and complaints and other behind-the-scenes spam-caused messes the rest of us don't see. AOL talks of spam as "public enemy number one." Barry Shein, who started (and still runs) the world's first full-service dialup ISP, likens spammers to organized criminals, and calls spam "an organized, vicious, sociopathic thing" in this article, which spurred an interesting Slashdot discussion. So what should we do about spam? Ask Barry. One question per post, please. We'll post his answers to 10 of the highest-moderated questions sometime in the next week or so.

What's your e-mail address?

What is your e-mail address? I promise I will not sell it to third parties.

Collateral Damage

One of the greatest problems with spam-prevention techniques has to do with collateral damage. Can you see any solution to spam that either prevents or minimizes the damage to innocent bystanders, such as other users of a spammer's ISP?

has destroyed the usefulness of email though

I'd argue this collateral damage has destroyed the usefulness of email even more than spam has. It's simply an unreliable medium these days -- you never know if your mail got there or not, because it could have been silently dropped with no bounce message sent. Thus whenever I send reasonably-important emails now, I use either the phone or AIM to confirm it was received.

Re:has destroyed the usefulness of email though

scripsit Trepidity:

I'd argue this collateral damage has destroyed the usefulness of email even more than spam has. It's simply an unreliable medium these days -- you never know if your mail got there or not, because it could have been silently dropped with no bounce message sent.

There's another, more insidious effect. I have caught myself almost deleting important, legitimate e-mails because subject lines looked ``spammy'' on first glance. Something like 80% of the e-mail in my inbox is spam, so I delete more than I read. Eventually, something important is going to get deleted instead of read; heck, it may have happened already and I just don't know it yet.

Consequently, I never assume e-mail to be totally reliable.

Re:Collateral Damage

How about extension/modification to SMTP that ensures that IP addresses in e-mail headers are valid? I imagine a key system where the user requests a key from his ISP. This mail key is sent back to the user for limited time use, perhaps a day or when the DHCP expires and the user needs a new key. Of course this means filtering of SMTP on the ISP side which could be a big expense

Anyway the server looks at the from line in the header which now has a IP-key pair to see if it is valid. The server appends it's own daily key saying that it has checked the IP for validity.

On the recieving side, the server looks to see if the sending mail server is using this system, and does it's own filtering based on the IP addess (i.e. no 192.168.* or 172.28.* or other addresses reversed for special purposes)

Once this sytem becomes widely available, incoming servers can just ignore mail that does not conform to this system.

Ensuring IP address validity will be a big step in keeping spammers honest. If people could directly respond to spammers then we have sovled almost all SPAM abuse problems. Other valid SPAMs can be effectively filtered out on the client side. These steps will reduce SPAM effictiveness to a negligable level, while preserving valid emails from mailing lists and such.

Bayesian Filtering

Tried it? Like it? Have problems with it?

I use Popfile at home. It seems like the perfect answer to spam. What's your take on Popfile and other Bayesian filtering methods?

Re:Bayesian Filtering

You completely miss the point of Shein's tirade.

By the time it gets to your inbox, it has already cost your ISP money (time/effort/bandwidth) to deliver it. You just see what leaks through your ISP's filters, despite their best efforts.

I ask for mod-love for the first time ever here.

Regarding the Baysean Filtering question...

By the time (spam) gets to your inbox, it has already cost your ISP money (time/effort/bandwidth) to deliver it. You just see what leaks through your ISP's filters, despite their best efforts.

While in the short term I concur, in the long term I must cry au contraire.

If Baysean filtering makes its way to the general public -- or is introduced at an ISP level, then it will reduce the amount of spam that gets through to potential customers, and hence make each spamming less profitable.

The least profitable of the spam messages will dissapear, thereby reducing the loads on our mailboxes and on the ISP as a whole. Therefore, perhaps a better question is:

Is there a way to use Baysean Filtering to reduce the costs an ISP faces due to spam?

what's your opinion?

What is the best way to discourage spammers from spamming? (Aside from Dave Barry's idea of a hunting season and selling tags)

Kill 'em all....

If you could meet a spammer, what would you say? What would you do? What caliber would you use? Would you want someone to do it for you? Is $10,000 a head too much?

Nigerian spam killing in Prague

Ah, here is the reference. Diplomat shot dead in Prague [bbc.co.uk]

Re:If I ran an ISP...

I would just have a blanket, three strikes you are out policy. If someone complains about the content of your email three times, no matter the circumstances, you are outta there.

So if your best friend is infected with klez (or the latest variant) and sending messages that appear to be from you, if three people call to complain that you are sending them junk, you are outta there? Those are three complaints about the content of your email, and your policy says no matter the circumstances.

What if I don't like your political views that you've espoused on a political discussions mailing list and I call up your isp and tell them that your opinions about certain PICKWHATEVERPARTYYOUHATE Senators constitute a terrorist threat. After 3 of those complaints, you get dropped.

I wouldn't use an isp that didn't have some intelligence behind its decisions or didn't have an appeals process if I feel I was mistreated.

Fine, I'll ask

Would you like to consolidate your student loans while watching my 18 year old roomate take a shower, and then purchase some long distance phone cards?

Re:Fine, I'll ask

I'd love to, but I'm not feeling youthful at the moment, I need to go to the store for inkjet refills, and I've a terrible feeling my penis isn't long enough to satisfy her.

Actually, only one of the above is true :(

Spamming as a crime

Obviously the best step towards eliminating spam would be to make it a crime or easily punishable, but the nature of SMTP makes accurately tracking down the responsible spammer difficult at best and often time impossible.

What kind of changes would you make to the way email is handled to facilitate the elimination of spam?

SMTP

Do you think that we can fight spam efficiently by still relying on the outdated STMP for mail delivery?
What do you think should enhance/replace it?

Article suggestions

What were the best suggested courses of action that resulted of the article you published? What ones you or the community you feel that are more likely to be implemented?

Liberty and Security

If spammers are like organized criminals, one might make an analogy to protecting ourselves from orgnized criminals (say, terrorists) and possibly having to sacrfice liberties. I don't really endorse this myself, but lots of our lawmakers talk about needing find the "balance" between liberty and security.

Specifically with regard to spam, every proposed solution I've seen bothers me, in that it will restrict what I do myself now (legitimately) with E-mail. I already feel like collatoral damage in the spam wars, in that I can't just use my computer as a SMTP host to send mail (which is the Unix way to do it); rather, I had to configure my SMTP server to forward through an ISP SMTP gateway, as my cable modem is on a blacklisted range of IP addresses and some of my mail wasn't getting delivered. Well, OK, I was able to work around it, but it is already unfortunate that we can't just use whatever computer to send E-mail. More rigorous schemes will only make this worse-- for instance, requiring that the From: line match the SMTP host id where the message originates. Alternatively, a "per message" charge for E-mail, which yes would hamper spammers, will also hamper people who just happen to use E-mail a lot-- and,I guarantee you the spammers have easier ways of getting around that than the legimiate E-mailers do.

Is there any way we can cut back on spam without hampering legitimate use of E-mail even more than it already has been hampered in the battle against spam? Or are we just going to have to accept that we won't have the freedom to fully use E-mail the way it was intended in order to stop spam?

-Rob

Laws

Some people say that spam should be regulated somehow. The problem with this is how to craft laws that would affect spammers but not regular users of the internet. Ideally, the same laws would protect proper opt-in mailings.

Do you have any thoughts on these laws? I know that, as a non-lawyer, you probably can't do much for the actual wording, but what content would you have if it were totally up to you?

What would be the minimum actual cost?

Hi Barry,

What would be your actual dollar cost of spam, if you didn't spend much time and effort fighting it?

Let me explain...

I sometimes hear that spam has significant costs in bandwidth and storage but I don't believe it. As far as I can tell, SMTP traffic is at most 2-5% of net traffic. And a quick calculation shows that an ISP's costs for storing its users' spam are fractions of pennies on the dollar. (*)

You've likened spam to a DDoS attack on your mail servers. Stories about being flooded with traffic sound impressive but computers are so fast now, it's hard to put anecdotes into context. So I'm looking for dollar amounts. For a customers paying b dollars per unit time, an ISP like yours has to spend c dollars per unit time on servers that can handle those customers' incoming SMTP traffic. If this is significant, I'm looking for c over a times b :)

Obviously admins to run the servers are an important cost. But for purposes of this question, suppose you wanted to do the bare minimum. Say you set up the SMTP servers to use just a few of the less-intrusive DNSBL lists, like sbl.spamhaus, relays.ordb, or list.dsbl, and then ignored them as much as possible.

The next most common argument I hear is that customers will abandon ISPs that don't fight spam. But every ISP has the same problem, so this is really a competitive advantage issue except for the small percentage of users who are actually driven off the internet by spam.

Then there's outgoing spam but I don't imagine that's too hard to recognize and stop quickly.

Let me know what I'm missing...

(*) Thumbnail calculations of spam storage follow. Let's say J. Average ISP Customer gets 20 spams a day at 10K each, and deletes them only every 30 days. That's an average of 20*10K*15 = 3 MB of storage. If the ISP replaces hard drives every two years on average and its total storage costs are ten times the actual medium costs (for labor, backup, redundancy, downtime), then at today's hard drive prices, that spam storage will cost the ISP 0.003 * 10 / 2 dollars, or about a penny and a half. Over that same year, J. Customer pays the ISP $100+.

Re:What would be the minimum actual cost?

Your figures are totally incorrect. You obviously don't run your own mail server (or if you do, spammers have never found you).

For a start, ISP's get hit every day with repeated dictionary attacks where a spammer tries thousands of common usernames for each domain the ISP hosts. The sending hosts (usually a number of raped proxies) pipelines the SMTP sessions and doesn't wait for a response. Every single one of those emails chews up CPU, memory and disk space. It's a non-stop attack on your mail server queues.

When they get a miss, sendmail bounces the email to the postmaster and tries to deliver a bounce message to the forged FROM address, so your queues and disk fill up for days with this crap.

When they get a hit, it's even more disk space chewed up until the user downloads them. Some spammers are embedding HTML and graphics in their spam as well, so they are getting larger and larger.

I don't know where you saw 2-5% spam content. Most ISP's are seeing ten times that, unless they employ agressive filters which may be ideal for people who run their own domains but can be problematic for ISP's.

Re:What would be the minimum actual cost?

I don't know where you saw 2-5% spam content

The 2-5% he guesstimated was total usage of bandwidth by SMTP. I say guesstimate because I've searched for bandwidth usages by protocol and haven't been able to find (recent) data. Unless we can have reasonably accurate numbers from backbone segments it's going to be difficult to estimate just how much Spam really does cost.

I mean, if the OP is correct and SMTP only chews up 2-5% of the backbone, then it's not nearly as big of a problem as if it's chewing up 20% or more.

Even so, if SMTP only takes up 5% of the bandwidth and 80% of that usage is Spam, consider just how much cost savings could be realized from dropping SMTP from 5% to 1%.

RBL's

Thank you for participating

One of the few measures that can be taken against spam is the use of blacklists (for instance via DNS). There are a lot of pro's and con's for the use of DNSBL's. How do you feel about these? Should DNSBL's be governmentally regulated? Do you use any DNSBL? Should an ISP enforce certain RBL's (let say, of open relay's) on its customers?

Technological versus lawful.

Do you think that a technological solution, whilst imposing to everyone else the, well, the thechnological solution, is better than a law, against the spammers, like, putting them into jail, or like?

Bayesian filtering

What steps have you taken to prevent spam from entering your ISP's email system? Do you recommend any kind of spam filtering software to your customers that implements Bayesian filtering? If not, why?

Spammer Crackers

Is it time to apply the computer-cracking laws to circumvention of anti-spam filters? After all, the two are identical in effect (break into somebody else's system without permission, and indeed against an express prohibition).

ISP Tools

Do ISPs have the tools they need to prevent outgoing SPAM from their own customers? I look
at Sendmail and don't see anything that would allow you to throttle mail volume, check outbound messages for SPAM, restrict new customers etc. There isn't even anything built in that would warn you about a customer sending a million messages. It would seem that a few tools like that would be a big help to an ISP too small to develope its own.

Is there a resonable solution?

Given that junk mail in the regular mail is more acceptable (and I will mention that my wife (specially) does like to know when there's a sale on), and given that e-mail is the next big thing, what do you see as an acceptable solution/accord to spam?

I certainly am tired of deleting the penis elargement and Nigerian bank deposit e-mails, but where is the balance and how do we attain it, if ever?

Permission Based Solutions

I am currently using a permission based solution to block spam, called Choicemail [digiportal.com]. It works great since I know that there are no filters trying to guess what is spam and what is not. People on my white list get in, people who aren't get sent a message asking them to identify themselves.

The only drawback is that some people may possibly feel slighted that they are forced to go through such a process. But so far no one has complained. In fact, most people seem to be intrigued by the concept. If this type of spam blocking catches on, people will begin to expect it. Sort of like having to knock on someone's door before entering their house. It is a custom so pervasive, we feel strange just walking into someone's home, even a friends, without first knocking.

Sorry for the length of this post, and now to the question: How do you feel about this type of spam blocking?

why not whitelist?

Why hasn't any large ISP or enterprise seriously considered whitelisting mail? The traditional blacklist idea -- when I see spammers I'll no longer accept their mail -- is so easily overcome that many spammers don't even wait one generation to change addresses. Instead, bounce all mail you don't recognize, with a note to the sender on how to inform the system that you are a real user. Nearly all spammers loose their incoming account immedately, so this seems the natural choice. There's some more detail on this method at the TMDA project [sourceforge.net].

Blacklisting SMTP servers?

As far as I know, most spam originates from a relatively small number of smtp servers which are open for posting without identifikation. Where there ever efforts of blacklisting these servers and denying to accept mail from them, and if yes, with which results?

Or alternatively blocking whole ip-ranges of ISPs which deny to cooperate on this issue?

Can tech solve this?

Do you think that there will ever be a long-lasting technological solution (e.g. Bayesian filtering systems) to spam or do you feel that any technological counter measure will be circumvented fairly rapidly?

national "do not email" list???

I was just thinking about this... what if there was a national "do no email" list? I'm just wondering if something like that would be effective.

All spammers would have to (by law) query the "national do-no-email" database before sending out their crap.

I'm just wondering if something like that would be an effective way to cut down on the noise out there?

Spam Lawsuits

Do you think new laws that allow ISPs and end-users to collect damages from spammers on a per-message basis can be effective tools to reduce spam?

Spam and whitelists

Much has been made of the problems of blacklisting. Do you see whitelisting as a viable alternative, and (if so) what form do you think that it will take?

Acting Locally, Effecting Globally

Many posts talk about proposed changes to society, government, and technology to lessen the spam problem. However, an ISP has more insight into the problem than many others, and I thought I'd ask a question to tap that insight:

Given today's society, technology and infrastructure, what can an individual do that would be effective in reducing not only the personal strain of spam, but also lessen an ISP's burden.

What kind of strategies have you seen work. For instance, in particularly bad instances I'm prone to send an e-mail to [e-mail], [e-mail], or [e-mail], but usually never even get a response. Is there a better thing to do? Are there things that are absolutely the wrong thing to do (such as replying to a spam)?

In short, what would you like to see users do in response to spam today?

What legal pursuits?

What legal pursuits do you feel would be appropriate to deal with spammers? What penalties? Prison time? Just fines? Given that some spammers make large sums of money from their spamming activities, what scale of fines would be appropriate?

MTA Identification?

I'm thinking that if you really want to end spam, you'll need to do white-list authentication of mail servers that are allowed to talk to yours. Any reason you couldn't build your mail service using a web of trust? MTAs forwarding spam could easily be kicked out of the web of trust. Some sort of cryptographic identification would be nice too, so each MTA could verify that the message passed through the servers that its headers claim it did.

Sure it'd be a short term hit on the number of hosts you could exchange mail from, but eventually I think anyone who wanted to talk to anyone would have to get on.

isn't email filtering dangerous?

ISPs have tried to rely on 'common carrier' defenses in the past. However, if they start blocking SOME email, can they be held liable for mail that they DON'T block?

And can you selectively give up common carrier status? If you block some email but host anyone's web page, for instance, can you be sued successfully for objectionable content on those web pages?

Worst Practise

What is the most evil thing you have seen, so far?

Reply-to impersonation?
Embedded hypertext identifiers?

I'm sure it's much worse than that.
What would you do to stop that evilest of evil practises?

SPAM as a weapon?

I get the sense that Barry may be suggesting that there is an ORGANIZED effort to crush small ISPs though SPAM.

Barry, are you saying that SPAM might be being used as a WEAPON against smaller ISPs that can't afford the manpower to try and limit it?

This is a conspiracy theory which would certainly explain alot about smaller mail servers getting 200 pieces of SPAM per user per day (as some accounts I am familiar with do) while accounts with some of the "big boys" seem to get amazingly FEW SPAM.

some quick stats

Here at _NAMELESS_ISP_ we use postini as a front end for our mail services- postini keeps their filters current so that we can get on with our jobs here. We pay them a fee each month and they keep the spam out. Here's the past 24 hours of residential usage. (2.23.2003)

Total Messages: 155,610
Bytes: 1,198,581,670
Messages that got looked at: 91,140
Messages that got blocked: 76,657
% of bytes blocked: 53.0%

so 91k of 155k messages got filtered- the rest are people who turned it off cause they dont trust the system. It's perhaps safe to presume that the percentage is roughly the same if the rest got filtered, too. 76% of our email is spam! We've had our domain since 1994. Spam is defined as anything blocked by the postini filters, which each user can control a threshold on, so the definition of spam is subjective.

real problem

spam works... that's the root of the problem.

do you think there is anything that can combat this?

simply telling people that nothing will add three inches may not work as well as we hope for... stupid people are gullible.

Back to the 90s

If you had known back in the early 90s that spam was going to be the problem it is now, what steps would you have taken then to protect yourself and others from it?
For instance, what changes would you have advocated in the mail protocols and what standard procedures would you have told other ISPs to use to prevent spammers from getting a foothold in the first place?

Bandwidth consumed?

Do you have any statistics on how much of your ISP's bandwidth is consumed by spam? (And for comparison's sake, other stuff like p-2-p and Quake servers.)

To Bounce or Not To Bounce?

Should end users set up their SPAM filters to bounce the offending messages, or should they just get quitely filed into the SPAM folder?

I used Mailwasher for a while, which gives users the options of generating bounce messages while filtering. There is some personal gratification in making it look like my email address doesn't exist. But does it actually help, or does it just add to the ISP's bandwidth requirements?

I can't publish my email address anymore

A couple of years ago, I took my email address off my business cards.

I don't give out my email address to anyone I don't know well, and I change it every year. I tell people who need to get in touch with me to call.

All this is because I started getting 50 spams a day. Right now, it's impossible to post to a newsgroup, put an email address on a web page, or have an email address that's listed in any sort of a directory without getting tons of spam each day.

I agree with that article that email is a failure. Important/busy people just don't have time for it.

A friend of mine finished looking for a new full-time job. He sent out some resumes by email to the listed addresses, and some by Fed-EX. Only the Fed-EX ones got answers. Companies get so much spam that they miss good resumes coming to them!

Internet Mail 2000

What do you think of the IM2000 [cr.yp.to] system proposed by DJ Bernstein, the author of qmail? It is meant as a complete replacement for SMTP where the mail is left on the sender's server. The sender then sends a message notifying the recipient that a message is ready for pickup.

DJB claims that with this system bounce messages will be eliminated (if I read correctly).

false negatives vs. false positives

In the interview from InternetWeek, you seemed to not care about false positives. At what point do you care about false positives?

Ie. are you attempting to stop all spam, with the possibility of false positives an acceptable risk, or is there some sort of calculation that your organization uses to balance the false positives (mail rejected as spam that wasn't) against the false negatives (mail that was accepted, but was spam)

Best software solution?

What, in your experience, has been the most *cost-effective* spam-reduction software solution? Is it server-based, or is it some kind of client software?

cleetus

Should a new email protocol be created?

It seems to me that the existing email protocol has some fundamental problems that contribute to spam. It is basically impossible to authenticate who an email came from. Do you think that adding a new email protocol could solve these problems?

Specifically, if we created a second protocol that required that all email be digitally signed by the person listed in the "from:" clause and that the originating ISP guarantees this identity, wouldn't that solve most of the problems? The true identity of people who use the bandwidth I pay for to communicate with me seems like a fair thing for me to be able to insist on. I might even be willing to pay a little more to have such a system, although I would think such a system would be cheaper for my ISP, since the cost of carrying 33% garbage isn't there.

I should be able to say I want to filter email from Alan M. Ralsky of West Bloomfield, Mich or from any that passed through any ISP that cannot guarantee me that I can determine this. The problem is that Mr. Ralsky can send me email and I have no hope of identifying that it came from him. All that is required, it seems to me is for the leading ISP's to get together and create and enforce a standard that says your new-style email will be digitally signed with your legal name and that only ISP's that comply with enforcement practices will be allowed to use the new email protocol.

Claimed Opt-In Spam Lists

I am a Systems Administrator for a statewide ISP. We have found that blocking such domains as azoogle.com, topica.com, etracks.com, and other claimed Opt-In spammers has really cut down on spam complaints. We had to go as far as firewalling these 3 spammers since they were chewing our bandwidth to peices. EverBlur which was recently kicked off their provider, has stopped altogether.

My question is, do you see this as an effective method? Do spammers really quit after seeing their packets are being dropped? Why do they not?

Is a legal solution possible?

Lets pretend that congress takes up the issue of spam and passes a very restrictive law essentially outright banning it. COULD that be an effective way to prevent it, or would the international nature of the internet make it useless?

Where do you draw the line?

I worked a couple of years ago for a company that makes 'emarketing' software, and I managed the company's ASP for that software.

Most of the emails we sent out we're from internal, registered customers of the company. I would call these 'opt-in' emarketing messages that ranged from pitches to buy new or upgrade products, customer satisfaction surveys and automated replies for visiting a website and signing up.

There were, on the other hand, spammers. That is the only way to describe the quality of the emails they sent out. When I could query their databases and find email addresses of '[e-mail]' and other, similar non-customer addresses, there is no other way to classify it.

In either case, we never tried to hide or run away. We always used real email addresses and kept the same domain names. So, my challenges were, "How to I keep the 'good' customers from impacting the 'bad' customers?" I dealt a lot with CAUSE, the MAPS RBL and other organizations to keep the emails flowing.

So, here is my question: How do you, at the ISP level, differentiate between legitimate email marketing and Spam?

What is current SOHO SMTP server "best parctice"?

For those of us who are trying to set up incoming SMTP servers (or who are just curious):

What are the current "best practices" and state-of-the-art for the little guy (enterprise, small office/home office, little ISP, etc.) who:

- has some need or desire to directly serve inbound and outbound SMTP and

- has SOME time to sysadmin, but

- does not have the resources to throw several full-time-plus-pager sysadmins into the spam wars?

Recommendations for the small guys?

My friends and I are often responsible for small sites - our own colocated servers, small businesses, and the like.

What are your technical recommendations for us, to make your life easier?

For instance, I usually argue to require valid FQDNs in the HELO and MAIL FROM command, and reject anything claiming to come from myself or one of the RFC1918 reserved IP addresses. This is entirely content-neutral - I just see no point in accepting any message from somebody who can't be contacted in turn if there's a problem delivering the message.

But I generally don't bother with RBLs, and am philosophically opposed to IP redlining since it could easily lead to a world where a few corporations act as gatekeepers.

I know what impact this has on my sites, but does this cause problems for the large sites? Or does it help you as well?

Misguided efforts

How much users taking misguided antispam measures, such as

• Boucing messages with Mailwasher
• Having munged addresses where the "NOSPAM" is in the user part rather than in the domain part (that is, "[e-mail]" instead of "[e-mail]"), so your servers get hammered with invalid harvested addresses.
• Using often broken tools such as SPAMCOP to LART other ISPs?
• Does a significant number of problems from your user always come from the same users, or is the problem widespread?

are having a negative effect towards your own efforts at fighting spam, either by diverting ressources or simply being a nuisance?

How much of the SPAM complaints do you do receive are properly done (that is, with headers and sent to the proper ISPs)???

Quota systems...

So are techincal mechanisms feasable (like the following) or is United Nations level international legal enforcement required?

My technical proposal: people/companies purchase SMTP message-sends the way they purchase cell-phone-minutes:

• spammers who use open relays would saturate that relay's quota, and most of the spam thus relayed would fail to go out, thus the owner of the relay would have incentive to fix it, so they can send their own mail.
• spammers who send directly from ISP accounts would have to purchase large numbers of them in order to send a given volume of mail.

To enforce such a system, you would need to build a smart firewall that knew just enough SMTP protocol to read the RCPT To: lines, and count recipients. When a given sending host exceeds its counter for the week, poof! the firewall blocks further SMTP activity (or even all activity) from that host until someone clears it.

Backbones could limit individual ISP's with such a system, and ISP's could in turn limit individual customers; indeed they would basically have to, so that one customer can't ruin their SMTP quota. If the ISP doesn't enforce such a rule, their backbone tap enforces it for them.

If such infrastructure became widespread, the only way a spammer could send large numbers of messages would be to get large numbers of ISP accounts, which would hopefully cost them enough money to make it not worth their while anymore.

How about a "no filter day"?

It seems that law enforcement has no reason to get aggressive on this problem as long as companies such as yours bandaid it with technological measures. What do you think about a "no filter day", in which all of the ISPs remove their spam filters for 24 hours and let the world get first hand the full brunt of the traffic you're filtering? The outrage alone, if correctly managed, could get the appropriate authorities off their asses and go after these guys.

Regarding your MIT Spam Conference appearance

Mr. Shein, I saw your presentation at the MIT Spam Conference. You seemed to be suggesting that the way to reduce the cost of spam to mail server owners was to charge or tax spammers for the "privilege" of sending spam, and thus monetarily compensate the sites which receive and process it. I do not see how this can work for the large number of Internet sites, such as my own workplace, which are not ISPs, but which still have a significant spam problem.

I am a security technician and sysadmin for a research institution. My clients, who are scientists, are not interested in being paid to watch advertisements, or in having our institution funded by advertisements shown to them in email. We don't want to be paid to receive spam; we just want not to receive it. We just want the spam attack, the theft of our resources and our people's time, to stop. Do you see any way this can be reconciled?

Conflicts of interest...

Q: If ISPs are really all that upset about spam, why haven't they done anything about it?

It's patently obvious that ISPs could eliminate spam simply by blacklisting individuals who engage in the practice (and other ISPs who don't follow it). This is how credit ratings work, an area in which there is both a greater monetary incentive for misbehaviour and much lower (technical) barrier to entry.

Properly implemented, such an individual blacklist would eliminate most worldwide spam - since only a couple dozen individuals are responsible for more than 90% of the phenonema.

It seems to me that the real reason ISPs don't stop spam is due to base economics: spam houses pay money. So spam elmination has become a classic games theory problem - money you spend to search for spammers on your own network is wasted; you just have to respond enough to keep off the RTBL.

And because detection is always someone else's problem, spammers will continue to thrive in the time it takes to process the request.

Spam, Viruses, and Filtering

A few questions:
How would you grade the effectiveness of current filter techniques, and blacklists etc.

What filters/blacklists do you use, and how could they evolve so that you would feel comfortable using them? When choosing blacklists or filters, how do you measure the gains of blocking x% of spam against not-blocking y% of legitimate emails.

How do you regard the threat of spam in opposition to some of the major viruses. That is, viruses like "sapphire" that generate huge disabling traffic netwide, or like "code red" that - to this day - is still making attempts to access "cmd.exe" on my own linux box.

And lastly, as we all want to know, what do you think can be done to spammers to strongly discourage them from continueing their immoral practices.

Whose responsibility is false positives?

Hello, Barry--

As a World customer, I found last year that I was getting removed from several mailing lists I was subscribed to beause so much of their traffic was being bounced by World spam filters.

When I contacted customer support, they said that the messages must have contained strings that triggered the filters, and that the solution was for the lists to avoid using those strings in the future.

What strings would these be? Customer Support couldn't say.

So, if I wanted to use my World account to recieve my list mail, I would have to persuade all other list members to not use the filter-triggering words. And I would have to do this without telling them what those words were.

It seems to me that strong filtering of customer inboxes is one thing, but doing so with no provision for opt-out or whitelists interferes with the individual's right to get the internet servide he's paying for. Do you disagree?

HashCash?

Through my own travails with SPAM to my personal account, I've come to the basic conclusion that filtering out SPAM is a sisyphean task. No matter how good we make our filters, determined SPAMers will find a way through those filters. Blacklisting of open relays helps, really only punishes careless sysadmins, not the SPAMers who victimize them.

I see much more promise in technologies like HashCash [cypherspace.org] which force sending machines to burn CPU cycles in order to send their message. My question to you is, are you aware of this type of technology? Do you think it would be effective? And what do you think it would take to get such a technology deployed (standardization, ISP acceptance, MTA/MUA integration, etc)?

What if it were outlawed?

If the US passed a law outlawing spam, or provided a do-not-email list, with harsh penalties for breaking it, do you think it would help? I'm in WA state, we have an anti-spam law, it doesn't help.

Are spammers too hard and too numerous to track down to be worth it (and too poor to pay the fine even if caught)? Would spammers just move offshore and continue to spam?

550: 5.7.2 No mail for you

In order to make it prohibitively expensive for the Spammer, one has to enforce (or goad) spammer's human-intervention.

Using the spammer's last SMTP protocol leg, before your mail server closes it, why not do the following:

By not letting go of the (would-be spammer's) SMTP connection, one can consult the mail recipient white list. From an unknown sender, instead, save the entire email in a holding queue and send back the following SMTP error message:

550 This is the first time you have contacted [e-mail]. To ensure that the email you have just sent reaches "john" and that you are not a spam robot, please send another email to the same email address with a Subject of "MD5-12312AFCD7654." Once done, you ([e-mail]) will never get this message again from and "john" will finally get your email.

With a marriage of sendmail [sendmail.org] MILTER [milter.org] and Tagged Message Delivery Agent [sourceforge.net], one can shift the burden of automating the mail recipient white list back to the sender (like ICQ does).

With a tweak of the last leg of SMTP protocol, we, the email users, will have control over what is 200 and what is 5-f@cking-50.

What say you?

- Shamelessly ripped from the Seinfield TV episode "Soup Nazi."

Can you put a number on it?

About what percent of the messages that go through your ISP per day are spam? Can you guess what that spam costs you per day in the increased bandwidth and better computers you need to be able to handle it? Do many customers quit giving spam as the reason?

DNS Blacklists

Barry,

I've been an active anti-spammer for quite a while now and am quite proud of the knowledge I've acquired in the fight against spam. I even make good money off of filtering spam for others. As an anti-spammer I'm sure you've encountered folks that simply don't understand the purpose for a DNS blacklist. They claim it's prone to false-positives, dated information, legality issues, informally administrated, submission information isn't verified, hard to get removed from a DNSBL, or just plain silly (I actually had a person tell me this once). Most of these people make such claims due to a bad experience they personally had with a DNS blacklist at some point. It might be that they didn't get a newsletter they'd signed up for, when it reality the sender might actually use spam as a marketing tool. It could also be that they no longer get yahoogroups.com mail, when in reality they harbor spammers and take no action on abuse complaints. It could also be that they themselves had a MTA listed, when in reality they were incompetent mail admins and their MTA was an open relay. The last one is the worst of all. Unfortunately a large number of the people that have said these things somehow manage to call themselves mail administrators.

As a mail admin, I'm sure you have a better understanding than most about how much spam can hurt a business and can see the usefulness in DNS blacklists. How do you make the case for DNS blacklists when faced with the misguided biasness from those that simply don't understand?

How do you define spam?

There seems to be a lot of disagreement between spammers and their victims on what exactly is "spam". Lots of spammers claim that it's not spam as long as [it's not commercial | it's not porn | I bought an opt-in list | etc]. Some users don't mind diet pill ads but hate herbal viagra.

What do you consider spam? Is it unsolicited commercial email? Unsolicited bulk email? What about chain letters forwarded to you by your Aunt Ethel? Any successful legal solution will depend on a good definition.

Spammer spoofing with my email address

What can I do now about a spammer spoofing with my email address?

I'm currently getting hundreds of bounced, undeliverable messages from various organizations because a spammer is using my email address to spam others. The web site he's advertising is located in China, and I seem to have no way of finding the individual much less taking action against him.

What are my options?

criminalize relay rape

One of the easiest solutions I can see would be introducing laws to expressly criminalize relay rape, and give law enforcement enough teeth and incentive to prosecute regularly.

Upwards of 90% of the spam hitting our servers is relay raped off innocent 3rd parties. When you report the criminal trespass to law enforcement, they shrug their shoulders and say "there's no law against it" or "there's not enough fines to make it worth our time to prosecute".

Well, there should be.

What would you ask of legitimate opt-in marketers?

What would you request of legitimate senders of high-volume commercial email to make your job easier?

The question:

How can a legitimate "secure confirmed double-opt-in" mailing list operator avoid getting labeled as a spammer?

Currently, a company that follows all of the "guidelines" and does everything right, still stands a good chance of getting listed on SPAMCOP and other RBL lists based on a handful of complaints from clueless customers.

BCDE.COM maintains an nation-wide network of high-volume web sites. Access to the most basic site features is free, but all value-added features require that the user register -- The registration page includes very clear notice that that the "cost" of registration, of access to advanced features, is that the user will receive marketing email from BCDE.COM.

If you choose to "unregister", BCDE.COM will stop sending you email, and you will no longer be able to access the advanced site features.

Filling out the form on the site is just step one -- based on the form, an email is sent to the email address supplied, re-iterating the terms on the form, and providing a URL to "confirm" opt-in. The URL includes a secure hash to prevent spoofed confirmations. Once an address has been sent a registration request, it cannot be sent another request for a week (to prevent using the form as a flood attack).

Daily, BCDE.COM and their ISP(s) receive complaints from users and from SPAMCOP about the confirmation email, about the marketing email, about the "spamvertised" sites hosted at A.BCDE.COM which are promoted in the marketing email.

99.999% of the user base has no problem with this business model, and would prefer this approach to actually paying a subsciption fee for access to the "value add" site features.

How can an ISP known that a sending site that their customers complain about, or a customer that other ISPs complain about, is a legitimate business that is following all the "rules"?