Sympatico blocks port 25 in order to try to prevent you from using an SMTP other than theirs, to prevent the use of rogue SMTPs (see http://www.cutedgesystems.com/software/PostfixEnabler/) I do not use .Mac but the issue usually requires a server that is set up on a different port. My personal domain is set up password-validated on 8080 and this gets by both Sympatico and Rogers. Also using SSL does the job. I think, but do not know for sure, that .Mac addressed this some time ago.