Forum Discussion

Mig's avatar
Mig
Icon for Altostratus rankAltostratus
Jul 21, 2019

snat automap - floating ip choice

hello , for some of my Vservers automap is set and there is no direct floating IP on the egress vlan.

bigip will choose the 2 choice : Floating self IP addresses on different VLANs

 

if multiple floating self ip exist ( on different vlans ), what is the preference for the bigip ?

 

The SNAT Automap feature selects a translation address from the available self IP address in the following order of preference:

  1. Floating self IP addresses on the egress VLAN
  2. Floating self IP addresses on different VLANs
  3. Non-floating self IP addresses on the egress VLAN
  4. Non-floating self IP addresses on different VLANs

thanks

  • Nathan_F__F5_'s avatar
    Nathan_F__F5_
    Icon for Employee rankEmployee
    Jul 22, 2019

    Hi Mig,

     

    Based on the list you provided I assume you are referencing the following article.

     

    K7336: The SNAT Automap and self IP address selection

    https://support.f5.com/csp/article/K7336

     

    That article contains the following note:

     

    "Note: When there are multiple self IP addresses on the egress VLAN, the BIG-IP system alternates the addresses using a load balancing selection similar to the Least Connections load balancing method."

     

    Although that note specifies the "egress VLAN", I believe it also applies to the other VLANs as well. In short, if there were multiple self IP addresses on the other VLANs I would expect the BIG-IP to alternate between them as well.

     

    -Nathan F

    • Mig's avatar
      Mig
      Icon for Altostratus rankAltostratus
      Jul 23, 2019

      Hi Nathan,

       

      thanks for your help , it' s a good explanation when multiple self IP addresses are configured .

       

      Mig.