3 replies to this topic

[marek_w]

Hi all

Does anyone knows how to configure a Cisco router to open port for just one external IP address.

I'm using following command but does not seems to be working.

ip nat inside source static tcp (internal IP of the server) 8080 (external IP address) 8080 extendable

Thanks
Marek

[syedabbas]

Hi marek_w,

Welcome to our forum.

Please take a bit time to check our forum rules and please post Your querries in appropriate Section.

The Question which you posted whould be actually posted in "OPERATING SYSTEMS & NETWORK MANAGEMENT"

If you post in correct section you will get your querries answered soon.

Requesting Mods to Please move it to correct section.

Regards,
Syed Abbas

[MarkinManchester]

interface ethernet 0
ip address 172.16.10.1 255.255.255.0
ip nat inside
!--- Defines Ethernet 0 with an IP address and as a NAT inside interface.

interface serial 0
ip address 200.200.200.5 255.255.255.252
ip nat outside
!--- Defines serial 0 with an IP address and as a NAT outside interface.

ip nat inside source static tcp 172.16.10.8 8080 172.16.10.8 8080

As your example only has one address so the so the use of "extendable" is not required, in the situation below you would require it.

NAT extendable

IOS does not allow allow two static translation with the same local addresses. However there are situation where customer might require two identical local addresses to be translated to different global addresses. The keyword extendable is used to achieve this.

Example:

ip nat inside source static 192.168.10.60 239.10.10.10 extendable
ip nat inside source static 192.168.10.60 239.20.20.20 extendable

The keyword extendable allows several static ambiguous address translation, ambiguous being the same local address or same global address.

Mark

[talent pk]

ip nat inside source static tcp (internal ip) 80 (external ip) 80
actually you are using wrong port here

you might be using internal proxy port which is 8080,if you want direct you need to keep that single private pc out of proxy and give it a direct internet access via cisco router. just use the above command. otherwise your internal LAN proxy server will always be hurdle in NAT

remember NAT and proxy conflict

Edited by talent pk, 16 May 2012 - 03:25 AM.