Enter a colon-separated list of IP-addresses to listen on. You need to double the colons in IPv6 addresses (e.g. 5f03::1200::836f::::). If you leave this value empty, Exim will listen for connections on the SMTP port of all available network interfaces. If this computer does not receive e-mail directly per SMTP from OTHER hosts, but only from local services like fetchmail or your e-mail program (MUA) talking to localhost you should prohibit external connections to Exim by setting this option to 127.0.0.1 and therefore disabling listening on public network interfaces. IP-addresses to listen on for incoming SMTP connections:
