irule to distribute based on user agent

will this work ? when HTTP_REQUEST { if {[string tolower [HTTP::header User-Agent]] contains "msie6" or "msie7" or "msie8"}{ pool Pool1 }else { pool Pool2 } }

you have to repeat [string tolower [HTTP::header User-Agent]] (or set it to variable first and re-use it later) in if-condition.

e.g.

  set uagent [string tolower [HTTP::header User-Agent]]
  if { $uagent contains "msie6" or $uagent contains "msie7" or $uagent contains "msie8"} {

or you may use switch instead of if-condition.

e.g.

[root@ve11a:Active:Not All Devices Synced] config  tmsh list ltm rule myrule
ltm rule myrule {
    when HTTP_REQUEST {
  switch -glob [HTTP::header value "User-Agent"] {
    "*MSIE 6*" -
    "*MSIE 7*" -
    "*MSIE 8*" {
      pool qux
    }
    default {
      pool [LB::server pool]
    }
  }
}
}