Cisco Port Forwarding from 1841 to cisco switch

[bfeole001]

Hello,

I'm trying to get port forwarding working for cacti to go through the wan port of the cisco 1841 to an internal switch. My cacti server has access to the 1841 on udp 161 and that works. I can monitor the 1841 stats.

However, if I try to do cacti to the ip of the 1841 at a different port like udp 1246 and have that port forward to the ip of the switch on udp 161, it doesn't work. It's like the firewall is not allowing 1246. snmp is running on the switch and sudo nmap -sU-p 1246 125.125.125.125 (ip address of the 1841) shows that 1246 is open/filtered which I think means the firewall is blocking it. The access list says my cacti server is permitted.

I have this rule:

ip nat inside source static udp 10.100.0.246 161 interface FastEthernet0/0 1246

but it doesn't seem to help. Cacti still can't reach it when I tell cacti to use 1246.

Any help would be appreciated.

[Karsten Iwen]

1. Have you configured the WAN and LAN-interfaces of the 1841 for "ip nat outside" and "ip nat inside"?
2. Do you have an ACL on your external interface or are you running a firewall that needs to allow this port? Double check the order of entries that the new line really matches.

[Georg Pauwen]

Hello,

just to be sure, do you have any other NAT rules with the same source ? Because if you do, add the keyword 'extendable' to each rule:

ip nat inside source static udp 10.100.0.246 161 interface FastEthernet0/0 1246 extendable