The mailing list for listmasters using Sympa

["Silvers, Tim" <address@concealed>]

Hi. We are running Sympa 6.2.68 on CentOS 7 with Postfix as our MTA. We had a user report that some emails to their list are not being distributed. Logs show “headers too large (32768 max)” errors for these messages. The only reference I see to this limit is in Sendmail [1], but as I stated, we are using Postfix. I found nothing in the Sympa config in reference to header size either, just message size.

 

Searching this error turns up a lot of references to O365 email headers being rather long and running into this default header size limit; the sending site is using O365. The fix seems to be for other MTAs to increase the header size limit. But how do I do that?

 

Has anyone else encountered this problem?

 

[1] /etc/mail/sendmail.cf:#O MaxHeadersLength=32768

/etc/mail/submit.cf:#O MaxHeadersLength=32768

 

Thanks,

 

Tim