Cannot send e-mail to AOL addresses

[zeebubble]

Ok I know this doesn't sound like a pix issue, but it probably is. I have several clients that have AOL addresses, and I kept getting an error from my Exchange server saying that the delivery has been delayed and a list of the recipients. I got on the horn with AOL, and they directed me to a site that told me to increase the DNS packet size. There is no option to do that in the Pix web interface, (God help me if I have to open up the command interface) so I increased the UDP packet size from 1200 to 1500, and then to 2000. I still get the same message. Any ideas? Thanks so much!

 

[colinT23]

Hi,

Sounds more like an AOL issue refusing emails from non-static IP's (are you by any chance using DDNS ?)or Exchange servers/domains with no reverse DNS.

Regards Colin.

 

[zeebubble]

I'm not using DDNS. You're correct, it is an AOL issue, but they're not going to fix it just for me or all the other mainstream businesses that use Cisco routers.

 

[FloDiggs]

What you are looking for is the "fixup protocol" command. You can do this from the gui as well. The command would be "fixup protocol dns maximum-length 512", but you would replace 512 witch whatever size you deem necessary. Through the gui, you would go to Configuration --> System Properties --> Advanced --> Fixup --> DNS and then change the Maximum Length. I don't know how that will help with email, but that is how you increase the maximum DNS packet size.

 

[zeebubble]

FloDiggs,
Ok I tried that and it didn't work. I messed with that before and had it all the way up to 1500, but still no game. This is something that AOL told me I have to do in order to send e-mail through a Pix firewall. Has something to do with too many packets getting stuck somewhere, and if you increase their size the fewer but larger packets will get through. Thanks for your help!

 

[zeebubble]

Do the packet sizes have to be divisible by 8?

 

[FloDiggs]

Also, I don't know if it has to be devisible by 8, but I tend to make it that way. But let me get this straight: You have clients with AOL email addresses that you are trying to email and they are getting bounced back? Have you tried smtpdiag.exe to figure out what is actually failing? I sincerely doubt it is your firewall. I would double check to make sure you have a valid PTR record for your IP, create an SPF record, and then use DNSStuff.com to make sure you aren't on any RBLs.