XFF Universal Persistence iRule

Problem this snippet solves:

Simple iRule to read the XFF header on an incoming HTTP Request and use a Universal Persistence ID. Orginal iRule found to have an issue with multiple IP addresses in the XFF header for changed to only pass the first XFF IP.

I have updated the iRule line to account for systems where multiple 'X-Forwarded-For' headers have been added.

persist uie [lindex  [ split [HTTP::header X-Forwarded-For] "," ] 0]

to

persist uie [lindex [ split [lindex [HTTP::header values X-Forwarded-For] 0] "," ] 0]

thanks to the advice from Yann Desmarest. This could also be done with the 'getfield' command see Yann's comments below.

How to use this snippet:

Create iRule using following code (mine is named 'persist_xff_uie') Create Universal Persistence Profile with iRule set to 'persist_xff_uie' (or what ever name you assign to the iRule) Assign Universal Persistence Profile to Virtual Server (ensure virtual server has HTTP profile assigned)

Code :

# Name: persist_xff_uie
#
# To be used with UIE Persistence Profile
#
# Checks HTTP Request for 'X-Forwarded-For' header and if exists takes the first 'X-Forwarded-For' IP address as sets as 
# Persist identifier.
# If the 'X-Forwarded-For' header does not exist then the client IP address is set as Persist identifier.

when HTTP_REQUEST { 
    if {[HTTP::header X-Forwarded-For] != ""} then {
persist uie [lindex [ split [lindex [HTTP::header values X-Forwarded-For] 0] "," ] 0]
    } else {
persist uie [IP::client_addr]
}
}

Tested this on version: