Thanks for getting back to me Thomas. I've turned on session logging and will report back if I can come up with anything.Comcast is the only one I've had problems with other than a full mailbox. Hope I can get it figured out.

 Cruise
 

I've been trying for 2 days to send some emails to addresses on comcast.net. Here's the SMTP CLIENT results:

18:11:30: processing job MO00000C
Resolved MX for 'comcast.net' to 76.96.30.116
Connecting to 76.96.62.116
Connection error.
Attempting connection to alternate, 76.96.30.116
Connection error on alternate.

Any ideas what may be going on? Seems to be pretty slow on response when looking up the MX.

Cruise 

[quote user="Cruise"]

I've been trying for 2 days to send some emails to addresses on comcast.net. Here's the SMTP CLIENT results:

18:11:30: processing job MO00000C
Resolved MX for 'comcast.net' to 76.96.30.116
Connecting to 76.96.62.116
Connection error.
Attempting connection to alternate, 76.96.30.116
Connection error on alternate.

Any ideas what may be going on? Seems to be pretty slow on response when looking up the MX.

Cruise 

[/quote]

I would turn on session logging in MercuryE to see exactly what is going on.  FWIW, there may be some port 25 blocking going on because I can connect to these comcast MX hosts.

220 IMTA06.emeryville.ca.mail.comcast.net comcast ESMTP server ready
ehlo thomas
250-IMTA06.emeryville.ca.mail.comcast.net hello [209.128.94.2], pleased to meet you
250-HELP
250-SIZE 15728640
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 OK

I did get one 421 error where they said rDNS failed on their end.