Wed, 23 Jan 2008
Port 87
In our cluster, we run various instances of Apache on different ports. When we need another instance, we just add it to all cluster nodes to the next free port. We have started at ports 80 and 443, respectively, and now we use ports up to 88 and 451. And this is where the problem starts:
The Apache instances are usually accessed at port 80 or 443 of the cluster
IP address, which is then forwarded by IPVS to the appropriate cluster
node and port. However, from time to time we need to access the Apache
instance directly. To my big surprise, the URL http://some.cluster.node:87/
does not work in Galeon (altough
wget can access it without problem). Galeon says that
the server has dropped the connection. It is not true: tcpdump does not
show any outgoing packet from my machine to the port 87.
The fix is simple, at least for Galeon: add the following line
to your preferences (for my Galeon, it was the ~/.galeon/mozilla/galeon/prefs.js file):
user_pref("network.security.ports.banned.override", "87");
Apparently, all other browsers (not only Gecko-based ones) have this behaviour. They just refuse to talk to services running on port 87 (and some other ports like 21, 22, 25, etc.). I wonder how these ports have been chosen, because some other well-known ports like 136-138, and 445, are not on this list.