Ironport retransmission

[tanwer]

We have new exchange configured to send email to ironport all IP has been added as relay . When we send test email we see as ICID lost , did injection  debug and packet capture. Below are results from ironport to exchange. Kindly need your advise how to resolve this

[rickgardner]

Is this a new Ironport setup as well or existing installation that has worked in the past?

[tanwer]

existing installation we upgraded from exchange 2016 to 2019.

[UdupiKrishna]

Try running the packet capture on ESA and the exchange server at the same time if thats possible.

Re-transmissions indicate that the ESA isn't receiving an acknowledgement to these packets. Question is if the exchange received them and if there were responses sent back.

[tanwer · Accepted solution]

Yes we did packet capture on all Hop's during test email and found firewall ESMTP inspection was turned on for new exchange environment.