How to use irules to do SIP outbounding proxy?

one quick answer/guess about why sip_in_2 is hit is...

 

 

by default, BIG-IP create connection table for UDP traffic. and if return packet match existing connection table, bigip will treat that return packet as it belongs to previous created connection.

 

you may use packet trace to verify if 4-tuple match existing connection table or not.

 

use command line as examples below to see connection table

 

b conn

 

b conn show all

 

b conn client 1.2.3.4 show all

 

 

you may combine sip_in/sip_out irule together

 

or

 

you may try custom UDP profile with immediate timeout. in that case, bigip will not create connection table.

 

 

hope this helps,

 

Nat