It would be nice if we could customize connection timeouts, rather than waiting for the default timeout. It appears someone has submitted a patch for this in the past. I never saw any follow-ups to see if this was something that was being considered. http://lists.samba.org/archive/rsync/2006-May/015649.html
Isn't timeout option what you want: --timeout=TIME set I/O timeout in seconds If yes, I let you to close the bugs.
I'm looking for connection timeout, rather than I/O timeout. When I send a SYN and never get an ACK, it hangs until a default timeout. For example, a netstat only shows SYN_SENT. rsync: failed to connect to x.x.x: Connection timed out (110) rsync error: error in socket IO (code 10) at clientserver.c(107) [receiver=2.6.8]
Yes, I snagged that patch but apparently neglected to check it in. There was a little tweaking I wanted to do to it before accepting it, which I worked on a bit this morning: http://rsync.samba.org/ftp/unpacked/rsync/patches/contimeout.diff Since it's so simple, I'm thinking of including it in the 3.0.0 release.
The current development rsync has the --contimeout option.