Irule to get host name from ip

Something sort of below. You can either try to set a new variable for computer host or use a variable directly from the iRule.

Modify as needed. DNS server (8.8.8.8) would be your internal DNS or you can also use VIP.

when ACCESS_ACL_ALLOWED {
set pager [ACCESS::session data get "session.ad.last.attr.pager"]
set serverhost [RESOLV::lookup @8.8.8.8 -ptr $pager]
ACCESS::session data set "session.logon.computername" $serverhost
}