Ubuntu 10.04, running Postfix, smarthost via Comcast. The following solution fixed my Postfix problem: nano /etc/hosts REMOVE localhost from IPv6 section # The following lines are desirable for IPv6 capable hosts ::1 localhost ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters ff02::3 ip6-allhosts Restart the networking /etc/init.d/networking restart Now I am able to send emails outside my local network.
