Can no longer send mail. Suspecting /etc/resolv.conf shenanigans

Alerts are now down so would like to fix this properly:

delivery temporarily suspended: Host or domain name not found. Name service error for name=gmail.com type=MX: Host not found, try again

I have hunch my problems started when trying to figure out how to get the below working (i.e. you do not edit resolv.conf directly)

cat /etc/resolv.conf
nameserver 192.168.1.1
resolv.conf -> /run/systemd/resolve/resolv.conf

3

2 Answers

It looks like you're using the wrong smtp server. It's not gmail.com. It's probably something like smtp.gmail.com or imap.gmail.com. Check your Thunderbird, or whatever, app settings.

Update #1:

In /etc/postfix/main.cf set:

relayhost = smtp.gmail.com:587
relay_domains = gmail.com

then reload/restart postfix.

And probably some modification of this...

# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.
#
# TLS
#
smtp_use_tls=yes
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
#smtpd_tls_cert_file = /etc/postfix/newcert.pem
#smtpd_tls_key_file = /etc/postfix/newreq.pem
smtpd_tls_CAfile = /etc/postfix/cacert.pem
#
# SASL
#
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = 

3

Try adding these lines above the nameserver line that's already there:

nameserver 8.8.8.8
nameserver 8.8.4.4

This will use Google's name servers - just as a test to see if it resolves your email issue. If it does, then you can either configure networkmanager to use an external DNS like Google's, or you can check the setup of your network's DNS (your router for example).

7

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