Forum Discussion

fwwescom's avatar
fwwescom
Icon for Fog rankFog
Aug 13, 2024

Self-IP & SNAT

We are in the process of replacing our F5's with new ones. One question that came up was self-ip vs SNAT.

Can we not use self-ip and use only snat pool for the pool members and can the VIP and pool members belong to the same IP of the snat without using a self-ip or do we need the self-ip?

 

Example=

VIP=10.2.2.254

SNAT Pool=10.2.2.250 

Pool Members=10.2.2.10 & 10.2.2.20

--------------------------------------------

Current topology:

VIP=10.10.10.20

Pool Members: 10.20.20.10 - 10.20.20.30

Self-IP:10.20.30.10

 

Can we just use the SNAT pool instead of the self-ip scenario? or we need the self-ip?

Thanks and hope this can be answer!

 

 

topology
  • Aswin_mk's avatar
    Aswin_mk
    Icon for Cirrocumulus rankCirrocumulus
    Aug 14, 2024

    If the self ip and pool members are different vlan you may require a L3 rule in between to allow the traffic. Create a vlan and self ip in device in range of 10.20.20.0/24 and use automap n the configuration. 

  • Paulius's avatar
    Paulius
    Icon for MVP rankMVP
    Aug 14, 2024

    When using SNAT I always recommend using a SNAT Pool that uses the virtual server IP so you have a way of tracking what SNAT connections go where and you don't run the risk of exhausting the self-IP ephemeral ports that are used for things such as health monitors because with automap uses the self-IP closer to the destination pool member. You can absolutely use a SNAT IP that exists within the same subnet as the pool members as long as the F5 has a self-IP within that subnet.