Hello Support,

I'm running Xeams version 9.2, build 6320.  I've configured the Xeams server as a closed relay and added IPs to the allow list.  I tried using a hostname, both short hostname and FQDN, and relaying is not permitted.  I then removed the hostname entries and added the IP address and was able to send a message.  I've verified the sending host is resolving in DNS.  I'm sending the messages via Synametrics Email Sender.  The SMTP logs shows EHLO of the FQDN of the sending computer.  and a 250 "Pleased to meet you with the same FQDN.  Do I need to add my internal AD DNS servers into the Xeams configuration somewhere?  Are there any known issues with adding hostnames to the allow to relay list?

Thank you.

Hi,

The hostname must be resolved at the receiving, not the sender's end. Consider the following example,

• You're running Email Sender on a network that has an FQDN of myip.example.com, and the IP address is 1.2.3.4
• You add myip.example.com in the relay list in Xeams
• Before accepting a message, Xeams will perform an A lookup on myip.example.com and will only allow relaying if the IP address of this A lookup is 1.2.3.4

Using an IP address in the relaying screen skips the A lookup and, therefore, works.

The sending computer is internal has a static IP and valid A record in our internal AD DNS.

Is the machine running Xeams configured to your internal DNS?

The only explanation for this problem is that Xeams cannot resolve the name. Since you're sending these emails from an internal machine with a static IP, a better option is to use an IP address rather than FQDN.

The Windows Server running Xeams is configured to use our internal DNS servers.  I have no issue with DNS resolution.  I can resolve by hostname, FQDN, and IP. I also tried using the Windows HOSTS file. Is there a specific Xeams log file I can monitor the incoming connection?  

Try the following steps:

• Look at SMTPConversation.log right after sending a test message. Check https://www.xeams.com/xeams-log-files.htm for more information about log files. You should see the connection attempt in this file.
• Next, click "Tools". This will bring up a page allowing you to run a DNS Lookup. Try performing a DNS lookup using the FQDN that you have put in the relaying tab. It should return the IP address you see in SMTPConversation.log

I tried the DNS Lookup. 

DNS server used:  dns://10.x.x.x dns://10.x.x.x  (IP addresses of my internal DNS servers)

A: 10.x.x.x (matching IP of computer attempting to submit an email)

MX:  not found 

TXT:  notfound

Could you please also post the log snippet from SMTPConversation.log for this test email? I recommend leaving the IP addresses in the logs since they're helpful when troubleshooting. They're on your LAN and no one will have access to them on the Internet.

It's not the ONLY reason. How about the fact the relay config won't work if you use capital letters in the hostname? I'd say that's a bug on your end, especially if the DNS response has the same capitalisation. At the very least highlight that hostnames need to be lowercase in the interface