passive cookie persistence from iRule

Hmmm, I would have thought format would have done it:

when HTTP_RESPONSE {
   set addr "10.10.10.10:80"
   scan $addr "%u.%u.%u.%u:%u" a b c d e
   set cookie "[format %u [expr ($d<<24)|($c<<16)|($b<<8)|$a]].[expr 256*$e].0000"
   HTTP::cookie insert name "BIGipServerFP_pool" value $cookie path "/"
}

format returns a string representing the number. Scan returns an integer from the string, so with scan you've got two extra integer->string & string->integer conversions going on...