F5 is upgrading its customer support chat feature on My.F5.com. Chat support will be unavailable from 6am-10am PST on 1/20/26. Refer to K000159584 for details.

Forum Discussion

Swilky's avatar
Swilky
Icon for Nimbostratus rankNimbostratus
Apr 25, 2020

SNAT 1:1 - Map client public IP to nat pool IP

I have a situation were we have a BIG IP F5 load balancer in front of a MS RRAS server acting as a VPN concentrator. When a user connects to the VPN the radius auth is proxied through a Cisco ISE ins...
application delivery
BIG-IP
cisco ise
LTM
RRAS
snat
Andrew-F5's avatar
Andrew-F5
Icon for Employee rankEmployee
Apr 28, 2020

This isn't possible using SNAT pools.

You might be able to use an iRule similar to what's described here.

when CLIENT_ACCEPTED {
    snat "172.23.180.[getfield [IP::client_addr] . 4]"
}

The iRule above doesn't require any SNAT object be applied to the Virtual Server.

The iRule will use the last octet of the source IP to SNAT to 172.23.180.x.

∟ For example: Source = 1.1.1.50, SNAT = 172.23.180.50.

  • ZANOOB's avatar
    ZANOOB
    Icon for Cirrus rankCirrus
    Aug 29, 2023

    Hello Andrew,

    I am trying to have almost the same, however, to MAP the SNAP pool IP to be the same exact as the source.

    For example: if my client's IP is 172.1648.10 then SNAT also has to be 172.16.48.10. (one-to-one mapping).

    Can i apply the same irule (with SNAT set to none on the virtual server or SNAT set to SNAT pool?)

     when CLIENT_ACCEPTED

    { snat "172.16.[getfield [IP::client_addr].[getfield [IP::client_addr]}

    the last two octets will be replaced with the client's last two octets?

     Regards

    Zanoob