I have an application that tunnels serial over TCP/IP using a daemon.
It works by starting at boot-up (inittab) and grabbing one or more
pseudo tty devices (based on what you tell it). You can download the
daemon from http://www.stallion.com (look for svr_tty). For instance,
I tell it :
/dev/pts/4 <host_a> <port>
/dev/pts/5 <host_b> <port>
If the daemon starts by init when the box is coming up, the daemon is
able to use the defined pttys and it works perfectly. However, if the
machine is already up and running and the daemon either starts or
restarts, I'm not always ...