On Wed, Sep 23, 2020 at 11:49 AM Greg Wooledge <wool...@eeg.ccf.org> wrote: > > On Wed, Sep 23, 2020 at 10:30:15AM +0300, Anssi Saari wrote: > > Britton Kerin <britton.ke...@gmail.com> writes: > > > I'm using ssh from a debian box to a rasberry pi (sorta debian also :). > > > > > > For some reason ssh sessions seem to time out pretty quickly. > > How quickly, exactly? What is the actual message/behavior you see when > it happens? Are they both on the same LAN, or is there some complexity > in between them (especially a NAT router)? > > > Well, the keepalives themselves can cause a disconnect if the keepalive > > messages are not reaching the other end due to bad connection for > > example. Looks like by default in Debian client sends keepalives if > > server is quiet but server doesn't send keepalives to a client. > > The normal reason people need to use ServerAlive or ClientAlive is NAT. > If your connection from ssh client to ssh server goes through a NAT > router, the router may keep track of activity on that connection, and > drop the translation when it goes idle for 5 minutes or so. Forcing the > *Alive packets to happen every few minutes prevents a NAT timeout. > > If there is no NAT involved, then I agree with the previous suggestion > that this might be a shell's TMOUT variable. Are you sitting at a shell > prompt when the "timeout" occurs? Does the timeout stop occurring when > you're inside a text editor, for example?
Looks like NAT was the culprit, because top kept it alive. Internet has bogus advice on this one because it suggests ServerAliveInterval 1200 or something which I guess is larger than most firewall timeout. Thanks for all help good to see debian community still so good. Britton
