Context: I installed FC6 on my daughter's notebook during the Christmas break. Some time later, fetchmail stopped working. It turned out that fetchmail tries to inject local mail by using SMTP with localhost port 25 (reasonable). Sendmail IS listening to 127.0.0.1 port 25. /etc/hosts says localhost is ::1. This is the IPv6 version of localhost. So fetchmail is trying to contact ::1 port 25 but nobody is listening. Which part of this is wrong? How come fetchmail worked for a while after FC6 was installed? I fixed the fetchmail problem by changing the definition of localhost from ::1 to 127.0.0.1. In /etc/mail/submit.mc, the config file for the sendmail submission daemon, there is a pair of lines: dnl If you use IPv6 only, change [127.0.0.1] to [IPv6:::1] FEATURE(`msp', `[127.0.0.1]')dnl That looks as if you must chose between IPv4 and IPv6. That seems dumb. On my FC6 system (which does not handle mail), there are two lines defining localhost -- one with ::1 and the other with 127.0.0.1. On my daughter's system (now) only the ::1 line appears. Why? Maybe because she used the network gui to disable eth1 (for some reason her notebook started leaching connectivity from neighbour's WiFi instead of using her perfectly good wired connection). This seems like a bug, but I don't know which component is wrong: sendmail (for not listening to ::1). whatever whacked /etc/hosts (for losing 127.0.0.1 as localhost). I think that fetchmail is blameless. Except that the error message wasn't too clear.
