For more information regarding the security incident at F5, the actions we are taking to address it, and our ongoing efforts to protect our customers, click here.

Forum Discussion

Mate_132781's avatar
Mate_132781
Icon for Cirrostratus rankCirrostratus
Nov 18, 2015

Change HTTP host to selected pool member IP address

Hi, I have BIG-IP LTM 11.6 HF6 with public IP address and two WEB servers with private IP addresses in pool. Problem is that WEB server expects it's private IP address in host field in HTTP head...
application delivery
http host
iRules
LTM
pool member ip
VernonWells's avatar
VernonWells
Icon for Employee rankEmployee
Nov 19, 2015

Regardless of the route domain id, the syntax is the same, namely:

HTTP::header replace Host [getfield [IP::server_addr] "%" 1]


getfield
divides the text stream into a series of field delimited by the identified character (%, in this case), and returns the field identified by number. So the "1", in this case, means "the first field". Since the IP will be something like 10.1.1.1%10, getfield with % will divide this into two fields, namely "10.1.1.1" and "10". You want the first field -- i.e., 10.1.1.1 -- hence the "1".