Serverhostname always shows only 1 Exchange server in Messagetrackinglogs

Question

Hi All,
Need your help in advance, we have a load balancer, whose id has been shared with application teams to add as SMTP server, at the back of LB there are our Exchange servers, recently we were working on ab issue with one application team and they were testing the mail-flow with 5k, 50k mails, and what we found was, after running Get-mEssagetrackinglog, we could see that only 1 exchange server showing up under Serverhostname for the EventID RECEIVE.

Even when we checked the headers, it was this server that was showing as first hop, but, when checked the Clienthostname , it showed up different server.

Need to understand whether the LB has routed the mail to the server listed under Serverhostname or Clienthostname, so need to understand these 2 fields real deep.

Answer 1

The fields are described here:
https://learn.microsoft.com/en-us/exchange/mail-flow/transport-logs/message-tracking?view=exchserver-2019#fields-in-the-message-tracking-log-files

client-hostname The host name or FQDN of the messaging server or messaging client that submitted the message.
server-hostname The host name or FQDN of the destination server

So if one server was showing up as the first hop as the server-hostname, then the LB was routing to that server first.

Answer 2

Hi @Andy David - MVP
Thanks for the reply, in that case why we are seeing different exchange servers each time logged under clienthostname, and one more thing what we are worried about here is, why is LB hitting the same Exchange server again??

I understood it this way, i maybe wrong, but sharing my understanding to state my confusion clearly, I thought the servers under clienthostname picked up the message from LB and then routed it to the server under serverhostname.

When i googled through, I too found the same answers, but, I am not understanding where is the difference actually between these 2 fields.

Answer 3

The client would be the server sending the message.
If the LB is using the same Exchange Server each time, I would troubleshoot the LB. It may not be configured correctly or one of the servers may be disabled in the SMTP pool.

Answer 4

Ok, I get it now, thanks for the explanation.
server disabled in the SMTP pool in the sense, services of these servers or anything else?