Mike Nielsen <mike at getbent.net> wrote: > > There are some sites that I cannot send mail to, the connection always > times out. If from my linux firewall I telnet to the given smtp server > port 25 it won't connect. However if I telnet from a machine behind the > firewall (The natted boxes get the same IP as the router) I connect just > fine. It isn't every smtp host just a few that I have run accross. It > dosn't seem to be any particular type of remote host either, some > sendmail, some exchange. > > I can't seem to figure out what is going on. > > I have disabled the firewall and get the same result. > > Anyone ever run accross this type of thing before? Well, if your firewall (which I assume is also the machine running Sendmail) is running the 2.4 Linux kernel, make sure you do `echo 0 > /proc/sys/net/ipv4/tcp_ecn'. A number of routers and firewalls drop or otherwise mis-handle those packets. -- _ _ _ _ _ ___ _ _ _ ___ _ _ __ I almost had a psychic / \/ \(_)| ' // ._\ / - \(_)/ ./| ' /(__ girlfriend but she left \_||_/|_||_|_\\___/ \_-_/|_|\__\|_|_\ __) me before we met. [ Mike Hicks | http://umn.edu/~hick0088/ | mailto:hick0088 at tc.umn.edu ]