topic ASA v8.0(5) Port Forwarding in Network Security

ASA v8.0(5) Port Forwarding

desmond.liew — Mon, 11 Mar 2019 21:47:13 GMT

Hi All,

This should be a straight forward solution for all but I am having some issues regarding port forwarding in Cisco ASA. Say my ASA is using a public IP 200.0.0.2/24, its default route is 200.0.0.1. I have two servers internally on 192.168.1.2 and 192.168.1.3, both a web server.

If I do:

Static (inside,outside) tcp interface www 192.168.1.2 www netmask 255.255.255.255

Access-list ACLOUTSIDE permit tcp any host 200.0.0.2 eq www

Access-group ACLOUTSIDE in interface outside

This works... However if I do this:

Static (inside,outside) tcp 200.0.0.3 www 192.168.1.3 www netmask 255.255.255.255

Access-list ACLOUTSIDE permit tcp any host 200.0.0.3 eq www

Access-group ACLOUTSIDE in interface outside

It doesn't work. I used ASDM and tried to create a Static PAT rule and it produces the same results above which also doesn't work. I did a packet-tracer and ASA sees it as okay. Anyone ever encounter this issue?

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ASA v8.0(5) Port Forwarding

Julio Carvajal — Mon, 07 Nov 2011 18:54:07 GMT

Hello Desmond,

The best thing would be to do captures because as I can see here the configuration is the one required to allow this connections.

Can you do the following capture and attach it to the case on a pcap format:

access-list capin permit tcp host 192.168.1.3 eq 80 any

access-list capin permit tcp any host 192.168.1.3 eq 80

access-list capout permit tcp any host 200.0.0.3 eq 80

access-list capout permit tcp host 200.0.0.3 eq 80 any

capture capin access-list capin interface inside

capture capout access-list capout interface outside.

Then try to access the web server from the outside and download the captures via HTTP, for this do the following:

http server enable

http 0 0 inside

And then on a local host go to a browser and :

https/insideipaddress/capture/capin/pcap

https:/insideipaddress/capture/capout/pcap

This will show us what is going on.

Regards,

Julio

Re: ASA v8.0(5) Port Forwarding

desmond.liew — Tue, 08 Nov 2011 12:00:52 GMT

hi Julio,

This is embarrassing. I was doing a parallel firewall migration remotely when the port forwarding commands didn't work. I took a rest and I checked about an hour ago (didn't check until then) and the port forwardings are working now. I am not sure why but it might have been to do with ARP on the Internet router side. Thanks for the packet capture commands. It might help me out one day.

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ASA v8.0(5) Port Forwarding

Julio Carvajal — Tue, 08 Nov 2011 17:18:39 GMT

Hello Desmon,

Do not worry, it is great to hear that everything is working fine with the ASA.

Please mark the question as answered.

Have a wonderful day,

Julio