Note: Server in this example is named atlantis.example.com.
First, we need to check our hostname
atlantis:~# hostname -f atlantis.diabmon.com
If hostname did not return FQDN of your server edit
/etc/hosts. You should see something like this, if not, change according to your IP address and server name.
127.0.0.1 localhost YOUR-IP-ADDRESS atlantis.example.com atlantis
Now check your
Change the names to match your server name and reboot the server. Run
hostname -f again and you should see
Now, we need to check that our DNS servers have an MX record for our example.com domain. Install DNS utilities:
apt-get install dnsutils
We are going to use
host to check information about our domain:
atlantis:~# host example.com example.com has address YOUR-IP-ADDRESS example.com mail is handled by 0 mail.example.com.
We can see, that the mail for our domain is handled by mail.example.com. Now we must make sure that mail.example.com points to the same address as our server (atlantis.example.com).
atlantis:~# nslookup mail.example.com Server: YOUR-DNS-SERVER Address: YOUR-DNS-ADDRESS#53
Non-authoritative answer: mail.example.com canonical name = example.com. Name: diabmon.com Address: YOUR-IP-ADDRESS
It would be also nice if your reverse DNS points to the same name (atlantis.example.com)
atlantis:~# nslookup YOUR-IP-ADDRESS Server: YOUR-DNS-SERVER Address: YOUR-DNS-SERVER#53 Non-authoritative answer: YOUR-IP-ADDRES-REVERSE.in-addr.arpa name = atlantis.example.com.
If they do not match. Ask your ISP to change this for you.