WL500GP Problem with FTP (21) port

[XTX]

I have a wl500gp with original asus firmware 1.9.7.0.

Last week i've performed some penetration tests for a company, and just for fun i've aslo port scaned my home IP. And I found out that the router responded to port 21 (FTP). The port was closed but it was stil visible, due to packets being rejected and not droped. All other ports were not responding (like it is suposed to be as I'm not running no server or something similar) only 21 was visible.
I then tried to stealth it in the router intern firewall (Wan to LAN filtering) but the port still rejects packets instead of droping them.

So I'd like to know if there is a default ftp server running on the original firmware (as far I know there is only a web interface) and if there is a way to "make" the router drop packets to the 21 port instead of rejecting them ?

PS
A friend of my has the same router and beeing a big web-port-scan sites fan (grc.com & stuff) he also founf out that on his router the 21 port was responding...


Cheers,

Bostjan

[ghoulr]

Do you set the "usb application->share nodes->FTP mode" to disable?

[XTX]

yes i did that, but there is no difference. The port is still accessible.
I can even connect to it (ftp 21)from wan side but the connection is after 2 seconds terminated by the router. So the port is still active:confused:

[calaba]

According to:
http://vip.asus.com/forum/view.aspx?id=20061005054658924&board_id=11&model=WL-500gP&page=1&SLanguage=en-us

the workaround should be:

The way to do it, is to enable the FTP server and then set up a virtual server under NAT Setting. The Local IP should be an unused IP address (e.g. 192.168.1.200), the port should be 21 and the protocol TCP. This will completely stealth the port 21, since all traffic is routed to a computer that doesn't exist.

ric.