Re: An SMTP protocol error occurred when sending to AOL and Compuserve

2 things to check:
1. correct reverse DNS registration for your sending mail server
2. firewall settings - cisco PIX firewalls with DNS Fixup enabled can only
pass 512 bytes of DNS response data by default. This is too small for AOL
or compuserve or some other ISPs with large numbers of mail servers.
Increase the size allowed to 1500.

"Mary" <mccato@xxxxxxxxxxx> wrote in message
news:e3T88qLqFHA.1040@xxxxxxxxxxxxxxxxxxxxxxx
> Email from our domain to AOL and Compuserve is not getting delivered. In
> the ESM, I see "an SMTP protocol error occurred" on the connectors. My
> users get a delivery delayed notice, then a delivery failure message 3
> days later with error "Could not deliver the mesage in the time limit
> specified. Please retry or contact your administrator. <server.domain
> #4.47>".
>
> I've contacted AOL - they are not blocking our IPs and have even
> whitelisted them; so mail from our domain should be accepted. They
> verified our reverse DNS entries; and I did their telnet test that shows
> our domain is not being blocked.
>
> This problem is only happening with email to AOL and Compuserve. Does
> anyone have any suggestions? Thanks
>
>
>


.

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