My friend is running a server on Beta 1.8 and we can't get to the nether. I'm confused, since everywhere I've read says you've been able to do that since Beta 1.6. Any ideas?
Is that a vanilla server? Look into the file
server.properties then set to true the properties
Is it a Bukkit server? Look into Permissions, maybe they are wrongly set up.
You can also try MultiVerse-NetherPortals if server is Bukkit.