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Sender Verification with Internet America

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bpogue99 View Drop Down
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    Posted: 16 March 2004 at 10:37am

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

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Keizersozay View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Keizersozay Quote  Post ReplyReply Direct Link To This Post Posted: 16 March 2004 at 11:16am

Hey Bill,

I have gone round and round with air-mail in the past, and long story short, they are idiots.
http://www.logsat.com/spamfilter/forums/showmessage.asp?messageID=1934
http://www.logsat.com/spamfilter/forums/showmessage.asp?messageID=2072
these are my two previous posts about this same issue. they simply refuse to cooperate. I ended up having to accept mail with a blank sender so my people could communicate. sorry to burst your bubble but that is probably the only way to make it work. if you do figure something else out please post it so I can use it as well.

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bpogue99 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bpogue99 Quote  Post ReplyReply Direct Link To This Post Posted: 16 March 2004 at 11:39am

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

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Desperado Quote  Post ReplyReply Direct Link To This Post Posted: 16 March 2004 at 1:49pm

We had this diacussion way back ... follow the thresd:

http://www.logsat.com/spamfilter/forums/showmessage.asp?messageID=1934

Dan S.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Desperado Quote  Post ReplyReply Direct Link To This Post Posted: 16 March 2004 at 1:58pm
Keizersozay,
 
You are being way to polite by calling them idiots.  Sender verification is a security hole, not Spam prevention.  Here is a quote from Sendmail.org:

novrfy

When this privacy flag is enabled, sendmail doesn't allow remote sites to perform VRFY commands on addresses.

novrfy is the default and recommended setting. Turning this privacy flag off allows external "bots" to "Harvest" email addresses.

Regards,

Dan S.

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