Hi all,
My sendmail on FreeBSD 11.2-RELEASE-p9 is relaying mail to my internal Exchange server and is refusing to forward mail when one of the TO addresses has an invalid domain.
The mail has many recipients, including a valid one on my Exchange server. According to tcpdump, SMTP succeeds with MAIL FROM and RCPT TO, and proceeds to send the headers. As it iterates through the additional recipients, sendmail on FreeBSD does a name lookup on each one (trying AAAA, A, and MX records additionally with search domain permutations to each of the sendmail host's name servers) and when it fails (because the sender mistyped the additional recipient's addresses) it returns the error:
It's a misleading message as the "xxx" server mentioned (which is my Exchange server) is not actually any of the nameservers on which it fails (because it's not a DNS server).
Anyway, the question is: is there a way to turn off this function in sendmail?
NB:
Adding the domain bbb to /etc/hosts doesn't work as it seems sendmail does not check it.
My sendmail on FreeBSD 11.2-RELEASE-p9 is relaying mail to my internal Exchange server and is refusing to forward mail when one of the TO addresses has an invalid domain.
The mail has many recipients, including a valid one on my Exchange server. According to tcpdump, SMTP succeeds with MAIL FROM and RCPT TO, and proceeds to send the headers. As it iterates through the additional recipients, sendmail on FreeBSD does a name lookup on each one (trying AAAA, A, and MX records additionally with search domain permutations to each of the sendmail host's name servers) and when it fails (because the sender mistyped the additional recipient's addresses) it returns the error:
"aaa@bbb... Deferred: Name server: xxx.: host name lookup failure"
It's a misleading message as the "xxx" server mentioned (which is my Exchange server) is not actually any of the nameservers on which it fails (because it's not a DNS server).
Anyway, the question is: is there a way to turn off this function in sendmail?
NB:
FEATURE(accept_unresolvable_domains)
does not work (I think it only applies to the MAIL FROM header).Adding the domain bbb to /etc/hosts doesn't work as it seems sendmail does not check it.