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Simon Waters wrote: > > I'm still intrigued as to why we can't connect to your email server - > but I've eliminated everything I can think of at the DCGLUG server end. Back at the day job, and thinking like an ISP techie not a system administrator..... The problem is that connections to "nonexistence.co.uk", which set the flags for "explicit congestion notification" (tcp_ecn) are being dropped. This draft IETF draft from 2001 suggests this is a "bad idea": http://www.icir.org/floyd/papers/draft-floyd-tcp-reset-00.txt ...but they would say that as they are the guys who invented ECN ;) Since I doubt we are the only email server you'll want email from which sets these flags, I suggest you check firewall/firmware revisions as appropriate. I've switched ECN off on the box I use as an email server -- but I haven't added it to /etc/sysctl.conf, so come the next reboot..... Simon -- The Mailing List for the Devon & Cornwall LUG http://mailman.dclug.org.uk/listinfo/list FAQ: http://www.dcglug.org.uk/linux_adm/list-faq.html