Here's an interesting challenge... Internet America, airmail.net, apparently has implemented a sender verification process for all emails received. As explained by their tech department their server does this to avoid junk email. However, when their server does the sender verification our Spam Filter denies the request because it's not a mailbox server, it's only an email filter. When they do the sender verification it forms an email and then tries a basic helo, mail from, rcpt to... just to verify that the rcpt to passes. The rub with this is the following:

03/16/04 09:25:38:532 -- (8224) Connection from: 209.196.77.99  -  Originating country : United States
03/16/04 09:25:38:704 -- (8224) Resolving 209.196.77.99 - mx2.airmail.net
03/16/04 09:25:38:704 -- (8224) Bypassed all rules for: Administrator@ourhost.com from
03/16/04 09:25:38:735 -- (8224) Disconnect

They use a blank sender for the verification process. Internet America support is telling me to make my end RFC compliant by putting my mail server as the device anwering the sender verification, but they're using a blank sender?

BUT, if I add users to the Unfiltered white list... the verification will pass just fine. For example, that administrator@ourhost.com above passes the sender verification because its in the unfiltered. But if the sender is not in that list, the verification fails because the sender is blank. I've asked Internet America to put a valid sender in their sender verification email and things will work just fine probably.

Any thoughts on how to get around this? The CEO of one of my customers tries to email his lawyer who uses Internet America and it never goes through. <g>

Thanks!

bill

Sometimes the simplest issue is a huge mess with these ISP's. They keep demanding that I put my Exchange server at the front door... which isn't going to happen. To work around this I've had to open the following door with 209.196.77.* in the white listed IP's. I traced all the airmail.net servers that I've seen connect to this server and they are all in that subnet. This allows there sender verification to work with a blank email from. I've sent them copies of the logs and such, we'll see, they've been slow to respond but I'll let you know what happens.

Hope this helps!

bill