Hostname based Load balancing (prior to 11.6.0)
Problem this snippet solves: This code is initially developed to provide a forward proxy to Apple Push Notification Services. This code can easily be customized to load balance requests to any resolved FQDN. Several issues are solved here : Forward proxy for several Apple APNs services like gateway.push.apple.com and feedback.push.apple.com Hostname based loadbalancing for BIG-IP under version 11.6.0 Source address persistence using tables (because when using the node command, persistence settings doesn't works) How to use this snippet: Installation This irule can be installed on multiple VS at the same time or on a wilcard VS. During several tests, we configured the following Virtual Server settings : ltm virtual vs_wildcard_apns { description *.push.apple.com destination 192.168.20.200:any ip-protocol tcp mask 255.255.255.255 profiles { fastL4 { } } rules { irule_apns } source 0.0.0.0/0 source-address-translation { type automap } translate-address enabled translate-port disabled vs-index 9 } Code : when RULE_INIT { set static::nameserver "8.8.8.8" set static::max_age 1800 } when CLIENT_ACCEPTED { switch [TCP::local_port] { "2195" { set host "gateway.push.apple.com" } "2196" { set host "feedback.push.apple.com" } default { log local0. "virtual=[virtual], src=[IP::client_addr], dst=$dest:[TCP::local_port], action=reject, reason=\"Request not allowed\"" reject return } } # resolve the hostname using table or dns lookup if { [table lookup "$host.[IP::client_addr]"] ne "" } { set dest [table lookup "$host.[IP::client_addr]"] log local0. "virtual=[virtual], src=[IP::client_addr], dst=$dest:[TCP::local_port], action=resolve, reason=\"from table\"" node $dest [TCP::local_port] } else { set dest [lindex [RESOLV::lookup @$static::nameserver -a $host] 0] log local0. "virtual=[virtual], src=[IP::client_addr], dst=$dest:[TCP::local_port], action=resolve, reason=\"from dns\"" if { $dest ne "" } { table set "$host.[IP::client_addr]" "$dest" indefinite $static::max_age node $dest [TCP::local_port] log local0. "virtual=[virtual], src=[IP::client_addr], dst=$dest:[TCP::local_port], action=forward" } else { log local0. "virtual=[virtual], src=[IP::client_addr], dst=$dest:[TCP::local_port], action=reject, reason=\"DNS resolution failed\"" reject return } } } when CLIENT_CLOSED { table delete conn:[IP::client_addr]:[TCP::client_port] } Tested this on version: 11.3