We are having an issue with Sendmail that only started today.
I have a server that generates reports from a SQL database, and these reports are then issued via Sendmail as attachments.
The reporting server and the Sendmail server are located in different sites.
I started to get the following errror messgaes logged in Sendmail today.
collect: premature EOM: Connection reset by xxxx
SYSERR(root): collect: I/O error on connection from xxxx
We have done the following to troubleshoot.
1. Re-send the mail - same problem.
2. Check MTU settings on all devices - 1500
3. Send a mail from the reporting server with a small attachment - works with no problem.
4. Send the original mail and attachment from a server at the same site as Sendmail - same problem.
I am guessing that this issue is realted to the size of the attachment, which is 14.5Mb. This attachment is produced monthly and has gradually increased in size and it seems to have tripped some kind of threshold which results in this error, as the only thing that generates the error every time regardless of where it is sent from is a mail with the 14.5Mb attachment.
Can anyone help with this ? I assume that the issue is related to the config of Sendmail itself as we seem to have ruled out issues based on cross-site traffic and/or MTU mismatch.