Hello,
My customer (a chamber of commerce with 11 employees) has their own Small Business Server 2011 with Exchange Server running on it. All their computers are running Windows 7 and Office 2010. In May of 2013, they had a new VOIP phone system installed, which included a new Cisco firewall and they also changed from phone company DSL to cable company high-speed internet service. Ever since then, a lotof their outgoing email messages to various recipients at different domains are delayed and/or rejected. Threy have received various reasons for the email problems, such as:
- Your IP address appears not to be an email server<o:p></o:p>
- User unknown (referring to the addressee on the message)<o:p></o:p>
- #500 Firewall error<o:p></o:p>
- #550 4.4.7 QUEUE.Expired; message expired ##<o:p></o:p>
- This message hasn't been delivered yet. Delivery will continue to be attempted.
Something that is interesting is some of the rejections say they were generated by the chamber's own exchange server. Why would their own server reject their outgoing messages? Also, sometimes a message will be addressed to multiple recipients at the same domain and some will receive the message and others not, or a chamber employee can send multiple messages to the same recipient in the same day and some will be rejected, but most not.
Shortly after the new firewall was installed and they moved to the cable company for internet access, I found that their SPF record might be the problem in DNS, so I submitted a new SPF record to their ISP and I added it to their local DNS as well (I'm pretty sure I did that correctly). Another thing I found in my web searching was a setting to change on Cisco firewalls, so I had the VOIP support guy add, "no ip inspect name esmtp" to the configuration of the firewall. That did not help the email problems.
So, that's where I am. Chamber employees are still having some of their outgoing email messages delayed or rejected and I'm out of ideas. I hope someone can offer a new fix. Thanks,<o:p></o:p>
-J