RESOLV::lookup¶

[lindex [RESOLV::lookup $hostname] 0]

b db tmm.resolv.retry
b db tmm.resolv.timeout

Or via tmsh:

tmsh modify /sys db tmm.resolv.retry value < value >
tmsh modify /sys db tmm.resolv.timeout value < value >

RESOLV::lookup [@<IP>|@<virtual name>] [inet|inet6] [-a|-aaaa|-txt|-mx|-ptr|] <name|ip>

when CLIENT_ACCEPTED {
  log local0. "devcentral.f5.com is currently at IP [RESOLV::lookup @10.10.20.1 "devcentral.f5.com"]"
}

Results in log entry:
Jan 21 20:21:22 local/tmm info tmm[5018]: Rule resolv_test <CLIENT_ACCEPTED>: devcentral.f5.com is currently at IP 65.61.115.213

# Select the first returned IP address as the destination IP (inherits the destination port from the client's destination port).
when RULE_INIT {
   set static::dns_vs my_dns_vs
}
when CLIENT_ACCEPTED {

   # Get IP(s) for hostname www.example.com against 4.2.2.1 name server
   set ips [RESOLV::lookup @$static::dns_vs -a "www.example.com"]

   # Log result. If there are multiple IP's it could be a TCL list like {1.1.1.1 2.2.2.2 3.3.3.3}.
   log local0. "Looked up www.example.com and found $ips, parsed first element: [lindex $ips 0]"

   # Check if the first list element was empty
   if {$ips eq ""}{
      # Input wasn't an IP address, take some default action?
   } else {
      # Select the IP
      node [lindex $ips 0]
   }
}