Can't access CUPS web interface from another machine

[Kevin]

Hi,

I was previously able to access the web interface from another machine and now I can't.  The only thing I can remember that changed was that I'm now connecting to the machine on another network interface (i.e. I used to connect to it on 192.168.3.x and now I connect to it on the 192.168.1.x network.
I took that into account and updated cupds.conf to make sure that the server allows IPs in that range.

I checked (using netstat) and the server is listening on port 631 on all interfaces but when I try to connect from another machine's browser, it always fails, like as if it isn't listening.

Any thoughts on what it could be?

Kevin