I've just obtained a new router from my ISP after the older one started to have problems. The new one is bigger and uglier, but shares the same webUI.
On the previous router a portscan revealed port 23 for telnet was available, but the router just refused my connection when I tried to connect to it. The newer router only reports two open ports, and they are both for net traffic:
Starting Nmap 5.00 ( http://nmap.org ) at 2011-01-20 18:02 EST
Interesting ports on 192.168.0.1: