a small problem with /etc/hosts in FreeBSD 6.2

[Pollywog]

in my hosts file, I have a line that looks like this:

::1                    localhost localhost.mydomain.com


Is this line for IPv6 or is there some other reason for its presence?  It 
causes occasional problems, so I commented it out and I kept a similar line 
that points to 127.0.0.1

An example of the problems it sometimes causes is that if I telnet to 
localhost at port 25 I get this:

Trying ::1...
telnet: connect to address ::1: Connection refused