Interesting problem sending email

[ScottChapman]

SO, I am sending email from Zimbra like a champ.

But I am having difficulty with one form of email address.

I have an address of the form first@last.name

But the mail keeps getting defered. I know I can send using a different SMTP server. Here is the info from my log:
May 22 13:24:14 zimbra postfix/qmgr[3276]: 2A69417E01E3: from=<mail@myhostdude.com>, size=1229, nrcpt=1 (queue active)
May 22 13:24:14 zimbra postfix/smtp[17315]: 2A69417E01E3: host mx02.nic.name[198.41.1.56] said: 451 Spamhaus - IP Lookup (in reply to RCPT TO command)
May 22 13:24:14 zimbra postfix/smtp[17315]: 2A69417E01E3: to=<first@last.name>, relay=mx03.nic.name[198.41.1.57]:25, delay=455, delays=454/0.01/0.31/0.14, dsn=4.0.0, status=deferred (host mx03.nic.name[198.41.1.57] said: 451 Spamhaus - IP Lookup (in reply to RCPT TO command))
May 22 13:24:21 zimbra zmmailboxdmgr[17551]: status OK

[phoenix]

The error message at Spamhaus seems to define the problem, you should be using your ISPs mail server to relay mail. Is that what you're doing? Is this an NE or OSS Zimbra installation?

[ScottChapman]

I am using the OSS Zimbra install.

I don't have it setup to be using my ISPs SMTP relay, but I am guessing I should do that rather than try to have mine just go out directly to send email?

[phoenix]

I don't have it setup to be using my ISPs SMTP relay, but I am guessing I should do that rather than try to have mine just go out directly to send email?

That would probably your best course of action, you'll have no problems doing that. You will still be able to have remote users connect to your server and send via that. You also appear to not have a valid reverse DNS set-up, that will also come back to bite you at some stage - many mailservers will reject mail from a server that has no valid reverse DNS (and for sending to AOL, a 'domestic' IP address will also get your mail rejected).

You could get your IP removed from PBL but as Verizon policy seems to restrict you from sending email directly you'll only get listed again.

[MTecknology]

Just a thought. I may be completely off...

Are you using a static IP? If you're using a dynamic IP, then your ISP is probably blocking your port 25 and 465. I've encountered this before and had unexplainable messages come back. The second I switched from dynamic to static, everything started working.