Persistence with Subdomains

If you're using cookie insert persistence, the cookie name should start with BIGipServer, but also contain the pool name (Click here).

Try adding a logging statement to log each cookie name to find the exact name of the cookie(s) you want to modify:

when HTTP_RESPONSE {
   if {[HTTP::cookie count] > 0 } {
      foreach aCookie [HTTP::cookie names] {
         log local0. "Cookie name: $aCookie"
         if { $aCookie == "BIGipServer" } {
            HTTP::cookie domain $aCookie company.com
         }
      }
   }
}

If this fails, try using a browser plugin like HTTPwatch for IE or LiveHttpHeaders for FF to see exactly what the client is receiving.

Also, the ability to configure a domain on the persistence cookie might be a good feature to have included by default. If you think so, you might consider opening a case with support and asking for this feature to be added.

Aaron