F5 GTM response IP Public

Hi guy.

I have config GTM on F5 I4800. After config complete. I have try test, all any thing very ok.

But I have bought subdomain: abc.com.vn and config Delegation to IP Public for Listener. When config complete. I try test. But I can not reciver IP public 123.123.123.12 for ( Pool virtual : 10.10.10.10) ( It is IP NAT for 10.10.10.10 ).

I think that. I need config iRule, F5 response IP public eq = 123.123.123.12.

Please help me.