Load balance HTTP with NAT (outside to inside)

Unanswered Question
Dec 3rd, 2007

Hello everybody,

i have read some documents about cisco Load balance features (SLB) and it looks good, but unfortunately i can't use it on my 2811 router. So i have to do something to balance my outside to inside traffic. Here is what i mean. Let's say that we have two servers. Server A and server B. They both are connected to router 1. The goal to achieve is following: When someone tries to connect ip X (which is address located behind router 1, or on router 1), then the router should translate the connection to router X, and send it to ServerA or ServerB in round robin basis. I Read it in Cisco.com webside, but it doesn't work.

Here is my configuration:

ip nat pool DESTINATION x.x.x.9 x.x.x.10 netmask type rotary

ip nat outside source list TEST pool DESTINATION

ip access-list standard TEST

permit x.y.z.1

ar1.sof3#show ip nat statistics

Total active translations: 10 (0 static, 10 dynamic; 9 extended)

Outside interfaces:


Inside interfaces:


Hits: 1465 Misses: 8

CEF Translated packets: 37, CEF Punted packets: 719

Expired translations: 424

Dynamic mappings:

-- Outside Source

[Id: 1] access-list TEST pool DESTINATION refcount 10

pool DESTINATION: netmask

start x.x.x.9 end x.x.x.10

type rotary, total addresses 131, allocated 0 (0%), misses 0

Queued Packets: 0

I have a "ip nat inside" on outside interface, and "ip nat outside" over the inside interface (path to the servers).

The end result is that all TCP requests which are send to address X are getting translated ONLY to ip x.x.x.9. The ip x.x.x.10 never gets one.

Any suggestions? Is there something wrong with my configuration?

Thank you in advance!

I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
jjoseph01 Tue, 12/04/2007 - 17:05

Im not familiar with the config you are speaking of. I am familiar with load balancing with a content switch, which works well. Can you point to the document you found, so I can take a look at it? I know the 11500s and 6500 CSS blades work really well, but I have never done it with the solution you propose.

s.arunkumar Tue, 12/04/2007 - 20:37

Hi ,

u are talking abt tcp load balancing,Try out by changing your configuration making your outside interface with "ip nat outside" and inside with "ip nat inside".

change the your nat command with "ip nat inside destination list TEST pool DESTINATION ".


This Discussion