Hi I have a configuration with sip accounts which authenticate with the real name of the customers ex: customer1(a)sip.myvoip.dev customer2(a)sip.myvoip.dev ... INBOUND call of multiple numbers are connected with alias_db to the accounts ex: +331234567890 | sip.myvoip.dev | customer1 | sip.myvoip.dev | +331234567891 | sip.myvoip.dev | customer1 | sip.myvoip.dev | +341234567893 | sip.myvoip.dev | customer2 | sip.myvoip.dev | +341234567894 | sip.myvoip.dev | customer2 | sip.myvoip.dev | ... and all works perfectly. OUTBOUND call after authentication with the username kamailio change the caller id and the ip of my ISP-SIP-TRUNK to relay the call with the correct CID for the ISP using the variable $fn (display name in the From header) [SIP-GW-ISP] { #out with ISP route(CID); $ru = "sip:" + $rU + "@" + "IP_ADDRESS_MY-ISP"; route(RELAY); exit; } ROUTE[CID] { $var(caller) = $(fn{re.subst,/"//g}); uac_replace_from("$var(caller)","sip:$var(caller)@$fd"); } Is possible do it with a different approach for example using Remote-Party-ID , PPI P-Preferred-Identity ? Is possible to check if the customer uses the correct outbound number present in the alias_db table ? ex for customer1 only +331234567890 or +331234567891 numbers many thanks Luca