ken@gvax.cs.cornell.edu (Ken Birman) (01/25/91)
There are a few places where ISIS needs to make up a port number that should be unique and "safe" on all flavors of machines we use. Because some UNIX systems restrict these to the range 0-4096 while others allow all 16 bits, we can't let UNIX pick. So, ISIS has a few places (util/isis.c, clib/tk_connect.c, cl_isis.c) where it picks a base number (1900, 1950, 2000) and then increments it until it finds a free UDP slot. Jacob Levy at SUN has found a problem with this. It seems that several SUN products use ports in the range around 2000 for broadcasts of various kinds (i.e. 2003 is used by something they call "radio free SUN", a news service). So, ISIS risks receiving these packets. Naturally, this causes ISIS to complain; it normally won't crash but the complaint may look like a crash (a garbled message from msg_reconstruct is typical). Apparently the range around 3000 would be safer. If you see these problems, edit the listed files and move the base to something like 3246 (or pick your favorite random number). We'll work on this in V3.0 -- Ken