jyl@noam.Eng.Sun.COM (Jacob Levy) (01/29/91)
In article <51187@cornell.UUCP> ken@cs.cornell.edu writes: > >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 Ken mentioned port 2003 as being used by a program called "radio free SUN". A couple of corrections are in order, and then a comment about usage of ports in general: A. The specific net I am on uses this port number for a demo program (aka a *hack*) called "Radio Free Ethernet". This is *not a product*, and as far as I know costumers do not have it on their machines. B. The admin of the specific net I use chose this port number. He could just as well have chosen 8034 or any other number. Therefore there is no such thing as a "safe range". The port number my admin chose to use for Radio Free Ethernet was duly listed in the NIS database and thus the problem could have been avoided. I am not familiar enough with the services provided by NIS but I believe it would be easy for ISIS to discover whether a certain port is registered if it chose to check this, on SUN systems. I hope that this correction helps to clear up some points wrt Ken's message. --JYL
schwartz@groucho.cs.psu.edu (Scott Schwartz) (01/29/91)
Just out of curiosity, does Isis have an officially registered (with sri-nic or whoever) port number? If not, it might be a good idea to get one.