Why Are We on E-mail Blacklists?

LogicallyRogue asks: "I run an email server for a small webhosting company. We've crawled all around the email server to make it as secure as possible: tightened Sendmail's security, POP Before SMTP, denying non-authenticated relaying, using SpamCop DNS blacklist, etc. However, with all this in place, every few months, it seems that we have been blacklisted by some ISP somewhere. This month it was AOL. We had no warning, and we don't know why we were blacklisted. All the information we have is a single URL. We visit all the DNS blacklist services we can to be sure we are not on any of them. We send emails to the postmasters inquiring for more information (like perhaps a reason or copy of the email that made the ISP blacklist us) - however, those are usually bounced back because we are blacklisted. We've tried calling the Blacklisting ISP tech support - and usually get the stunned I-have-no-clue-what-you-are-talking-about silence. Have any other Slashdot readers experienced similar problems with blacklisting and the big ISPs?"

Comments

overzealous spam lists

[PapaZit]

Where I work, we have that problem frequently. Often, it's a result of an overzealous spam list that decides that because the spammer forged headers that make it look like mail passed through one of our machines, mail MUST HAVE come through that machine, so we should be blocked.

Call the ISP and ask which spam filtering or RBL services they use. The first-level drone won't know, but if you explain that you're being blocked and you need this information to fix the problem, you'll probably get transferred or get a call back from someone who -does- know. You'll probably discover that their filtering was overzealous.

Sometimes, you'll run into a knee-jerk admin who unconditionally believes anything the RBL tells them. It's best just to write off this ISP -- you won't convince them that you weren't sending spam. Put a custom "ISP admin is an idiot" bounce message in for that domain so that your users know why the mail didn't get through, then move on.

Of course, this assumes that you're already actively handling open relays and abuse on your end. That's part of the job, and you should check carefully to ensure that your setup is okay before contacting anyone.

RBL's aren't perfect...

[PunkeyFunky]

..and as such, shouldn't be relied upon as a "oh this is definately for rejection". My firm uses an RBL as a plug in to SpamAssassin. Just being in the RBL by itself isn't enough to get rejected, but it bumps up the score a bit. Unfortunately, because RBL's are easy to slave and use, too many people rely on them, when the use is now limited. Limited by the fact that the 'big' spammers are incredibly clever these days. Having said all that, it wouldn't surprise me if AOL started blocking addresses with the '@' symbol... ;) Lee -- 'I love spam. Come get me.'

AOL Blacklists dynamic IP's

[nemui-chan]

Are you using any sort of IP address that has been flagged by a provider as a dynamic IP address? AOL refuses email from ALL dynamic IP based servers... which kind of sucks for a lot of people that run their own servers.

In other news . . .

[dheltzel]

AOL announced today that they have corrected the "issue" with their mail servers rejecting email from IP's starting with 6. Currently email is being rejected from servers with IP's starting with 7. AOL will be publishing a schedule shortly at to when each range of IP's will have it's emails rejected.

When asked why the company is implementing this policy, Bob Harvey, AOL's Minister of Information, said that they had determined that 70% of the emails coming from those IP's was Spam, and the remaining 30% didn't look very important to him anyway.

Re:Dial-up or residential IP blocks, too

[slittle]

if someone not on your network can connect to port 25 on your server, then you're an open relay

iptables -I INPUT 1 -J REJECT -p tcp --dport 25

Wow, they're right! I'm completely spam free now!

AOL only looks one hop back

[Anonymous Coward]

We had a simular problem at the Web Hosting company where I work. Our clients are permitted to setup blanket email forwards to a selected address, that is all email to @ are forwarded without filtering to .. Some of them use AOL accounts, so they end up with SPAM forwarded to them (they asked to get everything so they get EVERYTHING). AOL has a "feature" that permits you to click "this is spam" when you delete it. This generates a SPAM complaint. AOL only looks at the last place that the email was delivered from for these complaints. Enough complaints and that server gets black-listed. So we have our customers getting us listed, even though our servers are NOT open relays, open proxies, require SMTP Auth and that we have a very anti-spam policy as part of our TOS. We have now instituted a policy of not permitting this kind of forwards to AOL accounts. BTW we have re-submitted our servers for testing at http://postmaster.info.aol.com and have been de-listed.

Re:Happens all the time How to solve AOL blacklist

[ToadMan8]

There is a phone number to call... (let me grab it) 703.265.4670. If you call that number, you talk to some actually intelligent and customer service minded AOL people. They will give you a call ticket number if not solve the issue right on the phone, and will follow through (read: call you back) if they can't solve it right away. Miami University got blocked recently, we solved it in this manner. Hope this helps!