I'm using Exim4. When I try to send email to root, the email stays frozen in the queue. I'm seeing the following messages in the Exim log: "remote host address is the localhost". What does this mean and how do I fix the problem?
Remote host address is the local host is an Exim error message which indicates that the sender or recipient's domain has your machine's hostname/IP, but Exim is not configured to accept mail for that domain.
Exim has a standard domainlist named +local_domains that pretty much every different Exim configuration system uses. See what domains are configured for your system by running:
exim -bP '+local_domains'
You will probably see a command that looks up a list of domains from a file. Put your hostname in that file and Exim should begin to work properly.