Mail services are the suite of services that provide mail delivery, retrieval, and processing.
Most mail services require a restart after changing a host name or IP address of the mail server. If you manually changed configuration files, you might need to edit them manually again. Additionally, some mail services require a full shutdown and startup (rather than a simple service reload) to get address and identity changes.
There are many places in the mail services configuration panes where you enter domain names, mail host names, relay host names, and mail addresses. Any change you make to the host name could potentially have an affect on the service. Double-check name and IP address settings carefully.
Mail services
IMAP and POP
SMTP
Antivirus and antispam
Certificates for mail services
IMAP and POP
Dovecot, the IMAP and POP service, loads the fully qualified domain name at startup and configuration reload. After a change, Dovecot must be restarted or given a SIGHUP command, at a minimum.
You must also restart if you manually edited the listen or ssl_listen parameters.
SMTP
Postfix, the SMTP service, is very sensitive to network address and identity changes. The information it stores about the host name, IP address, and network interfaces is only loaded once at service startup. To resume service after a change to the host name or the IP address, you must fully stop the service and restart it.
You must also restart it if you manually edited the inet_interfaces, inet_protocols, smtp_bind_address, myhostname, or mydomain configuration parameters.
Antivirus and antispam
ClamAV, the antivirus service, gets its listening address at startup as well. After making changes to the host name or IP address, you must stop and restart to resume service.
SpamAssassin, the antispam service, gets its configuration information at startup and can reload configuration data while running. To load new configuration data, restart SpamAssassin or give it a SIGHUP command, at a minimum.
Certificates for mail services
Mail servers that use SSL need new certificates. You might need to regenerate or repurchase the certificates. Use the Server app to import the certificates, then configure each service’s new certificate.