topic Server's NAT Address Not Changing in Network Security

Server's NAT Address Not Changing

FoxtrotRomeo — Mon, 11 Mar 2019 21:52:24 GMT

I added a new server and created a new static NAT assignment on the ASA 5510 to the server's IP. When I browse to the web to check what public IP it's reporting, it shows the wrong IP. I disabled the network interface on the server, ran "clear xslate", reenabled the network interface, ran "sho xlate" and while the correct translation was in the table, the server still reported the wrong IP address.

I even ran a packet trace and it showed the IP address being correctly translated to the proper public IP, but when I browse to the web I get the same erroneous public IP. Here is the result of sho xlate:

layer-1-firewall# sho xlate

42 in use, 813 most used

Global 10.10.2.0 Local 10.10.2.0

Global x.x.165.72 Local 10.10.1.10 <--erroneous Public IP that it keeps showing

Global x.x.165.70 Local 10.10.2.34

Global x.x.165.68 Local 10.10.1.40

Global x.x.165.76 Local 10.10.1.102

Global x.x.165.75 Local 10.10.1.101

Global x.x.165.74 Local 10.10.1.100

Global x.x.165.77 Local 10.10.2.29

Global x.x.165.78 Local 10.10.2.60

Global x.x.165.80 Local 10.10.30.18

Global x.x.165.73 Local 10.10.2.99

Global x.x.165.79 Local 10.10.2.118

Global x.x.165.82 Local 10.10.2.27

Global x.x.165.83 Local 10.10.2.180

Global x.x.165.84 Local 10.10.2.109

Global x.x.165.86 Local 10.10.2.122

Global x.x.165.67 Local 10.10.2.149

Global x.x.165.91 Local AIS-Firewall

Global x.x.165.89 Local 10.10.2.126

Global x.x.165.71 Local 10.10.2.152

Global x.x.165.87 Local 10.10.2.156 <---Public IP that it's supposed to be showing

Global x.x.165.88 Local 10.10.2.150

Global x.x.165.90 Local 10.10.2.198

Global x.x.165.85 Local 10.10.1.135

Global x.x.165.81 Local 10.10.2.65

...snip..

Server's NAT Address Not Changing

cadet alain — Thu, 17 Nov 2011 20:58:47 GMT

Hi,

post your config.

Regards.

Alain

Re: Server's NAT Address Not Changing

FoxtrotRomeo — Fri, 18 Nov 2011 14:15:48 GMT

The config is attached:

Server's NAT Address Not Changing

cadet alain — Fri, 18 Nov 2011 15:30:51 GMT

Hi,

Which internal IP should have which global IP?

Regards.

Alain

Server's NAT Address Not Changing

FoxtrotRomeo — Fri, 18 Nov 2011 15:35:47 GMT

As noted above, 10.10.2.156 is suppose to translate to x.x.165.87. Instead it's still showing up as x.x.165.72.

Server's NAT Address Not Changing

varrao — Fri, 18 Nov 2011 18:40:51 GMT

Hi,

This might be an old xlate not being cleared from the ASA, you can do:

clear local-host 10.10.1.10

clear xlate global xx.xx.165.72

and the xlate should be deleted.

Hope that helps.

Thanks,

Varun

Server's NAT Address Not Changing

FoxtrotRomeo — Fri, 18 Nov 2011 21:13:06 GMT

Varun,

Would these commands have an impact on current traffic? As far as I know, no critical services are bound to that IP anyways.

Server's NAT Address Not Changing

Julio Carvajal — Fri, 18 Nov 2011 21:44:28 GMT

Hello Fox,

These commands are going to do the following:

clear local-host 10.10.1.10: It will clear the entries attached to the ip address of 10.10.1.10 on the local-host state table so the connections of that host are going to be disconnected.

clear xlate global xx.xx.165.72: Will do the same thing but this on the xlate table.

They are going to clear the connections for that especific IP address so if there is a TCP connection it will be disconnected, you will need to create the connection again and the new entries will be attached to each state table on the ASA.

Hope this explains a little bit of the local and xlate table.

Regards,

Julio

Server's NAT Address Not Changing

FoxtrotRomeo — Fri, 18 Nov 2011 22:50:58 GMT

I found the problem. It was a double Natting issue. The 5510 sits in front of a 5520 on the internal network (10.10.1.10) where the server sits. It was being NATTED as 10.10.1.10 and thus got the .72 address. Once I added a static NAT entry on the inside firewall the issue was resolved.