Created attachment 235350 [details] experimental patch DNS server may receive DNS queries related to tmux. The following is an excerpt from my ISC BIND log. 19-Jul-2022 15:54:30.421 client @0x803584960 ::1#59707 (tmux\(67594\).%0): view internal-in: query: tmux\(67594\).%0 IN A + (::1) 19-Jul-2022 15:54:30.421 client @0x803584960 ::1#60153 (tmux\(67594\).%0): view internal-in: query: tmux\(67594\).%0 IN AAAA + (::1) This query seems to be sent when a user whose login shell is tcsh/csh creates a new pane of tmux. This is probably related to the function getremotehost in /usr/src/contrib/tcsh/tc.func.c . The patch is an experimental patch to stop this DNS query. This patch misleads tcsh into thinking that tmux is an X server connecting to a unix domain socket :)
The issue was discussed before: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=204429
(In reply to Herbert J. Skuhra from comment #1) Then this report will be closed as a duplicate. However, X server that use the /tmp/.X11-unix/X0 socket register :0 to utmp. How about solving the problem by using a similar format? Since tmux also creates and uses sockets in /tmp/tmux-${uid}/*.
As this also happens on NetBSD (9.99.98) maybe this should be discussed in a tcsh (or tmux) group/mailing list.
This is already a known problem to many, and if the upstream does not fix, then this is probably the specification. So I will close this as only a suggestion on how to fix this problem for those who are concerned about it. *** This bug has been marked as a duplicate of bug 204429 ***