- Red Hat Enterprise Linux (RHEL) 8.0
postfix MTA can ignore
RES_DNSRCH resolver flags which will result in not searching hostnames in the domain.
For example with the following
# postconf -e "smtp_host_lookup = dns" # postconf -e "smtp_dns_resolver_options = res_defnames, res_dnsrch" # postconf -e "relayhost = [smtp]"
If the domain of the mail server is
example.com it will not use
SMTP mail server for relaying.
This problem can be resolved by addition of the
native to the
smtp_host_lookup configuration parameter, i.e.:
# postconf -e "smtp_host_lookup = dns, native"
Then it will behave the same way as in the Red Hat Enterprise Linux 7 and it will search the domain.
Fix release reverting to the original behaviour is tracked by public Bug 1723950
Resolver code in
postfix has been rewritten and improved. After the rewrite it used the
libresolv call instead of the
libresolv call for DNS resolving, thus it didn't process the search rules controlled by the
RES_DNSRCH resolver flags.
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