# Snat in NHLD with alternate server

**URL:** <https://community.a10networks.com/t/snat-in-nhld-with-alternate-server/828>\
**Category:** aFleX\
**Tags:** snat, aflex, nhld\
**Created:** [March 12, 2024, 3:46pm UTC](https://community.a10networks.com/t/snat-in-nhld-with-alternate-server/828 "2024-03-12T15:46:59Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![anfovar](https://avatars.discourse-cdn.com/v4/letter/a/bc79bd/32.png) [@anfovar](https://community.a10networks.com/u/anfovar)\
**Post date:** [March 12, 2024, 3:46pm UTC](https://community.a10networks.com/t/snat-in-nhld-with-alternate-server/828/1 "2024-03-12T15:46:59Z")

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Hi  
I have this scenario in a client´s infrastructure where they have 2 Internet links in active pasive mode

slb server LINK-1 20.20.20.1  
alternate LINK-2  
port 0 tcp  
port 0 udp

## slb server LINK-2 30.30.30.1 port 0 tcp port 0 udp

## slb service-group SG-INTERNET-TCP tcp 0 member link-1 0 slb service-group SG-INTERNET-UDP udp 0 member link-1 0

## slb virtual-server WCARD-VIP 0.0.0.0 &nbsp;port 0 tcp no-dest-nat service-group SG-INTERNET-TCP source-nat auto aflex&nbsp;SNAT &nbsp;port 0 others no-dest-nat service-group SG-INTERNET-TCP source-nat auto aflex&nbsp;SNAT port 0 tcp no-dest-nat service-group SG-INTERNET-UDP source-nat auto aflex SNAT

## aflex SNAT when CLIENT\_ACCEPTED { if { [IP::addr [IP::local\_addr] equals 192.168.1.100] } { snatpool STATIC-1 }

ip nat pool STATIC-1 20.20.20.5 20.20.20.5 netmask /24  
ip nat pool STATIC-2 30.30.30.5 30.30.30.5 netmask /24  
When the user 192.168.1.100 starts a comunication to the Internet it will go over LINK-1 with the Public src IP 20.20.20.5 as expected but if LINK-1 fails it will continue using STATIC-1 pool nat

How can I configure the aflex to use STATIC-2 nat pool when LINK-1 is down?

Thanks for your help!

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**Author:** ![dquinn](https://avatars.discourse-cdn.com/v4/letter/d/858c86/32.png) [@dquinn](https://community.a10networks.com/u/dquinn)\
**Post date:** [March 12, 2024, 5:01pm UTC](https://community.a10networks.com/t/snat-in-nhld-with-alternate-server/828/2 "2024-03-12T17:01:03Z")

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try replacing source-nat auto with a nat pool group. ACOS will apply correct member for outbound route.

ACOS(config)# ip nat pool-group outbound-nat-group  
ACOS(config-pool-group:outbound-nat-gro)# member STATIC-1  
ACOS(config-pool-group:outbound-nat-gro)# member STATIC-2

slb virtual-server WCARD-VIP 0.0.0.0  
&nbsp;port 0 tcp  
no-dest-nat  
service-group SG-INTERNET-TCP  
pool outbound-nat-groupACOS

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<div class="post-metadata">

**Author:** ![anfovar](https://avatars.discourse-cdn.com/v4/letter/a/bc79bd/32.png) [@anfovar](https://community.a10networks.com/u/anfovar)\
**Post date:** [March 12, 2024, 5:39pm UTC](https://community.a10networks.com/t/snat-in-nhld-with-alternate-server/828/3 "2024-03-12T17:39:31Z")

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Thanks, I will try it.