Hello Sergiu, now its better understandable. Just looked briefly to the code, the function works more or less like this: - it will take the URI and resolve it to an IP address - it will then compare this IP to the dispatcher nodes (depending on the mode to all or one group) So if there is a DNS name in the dispatcher list node entry, it will not match. You could try as a workaround to add all IPs of the FQDN (e.g. deactivated or with higher priority) to the dispatcher list as well and see if it works then. If yes, then the dispatcher module needs probably some extension. Cheers, Henning Am 27.08.19 um 15:56 schrieb Sergiu Pojoga: May be I didn't provide sufficient details, so I'll elaborate. I'd like Kamailio to 'talk' to only known dispatcher gateways, so in the REQINIT route I do: route[REQINIT] { # Silently drop requests from unknown gateways, very strict mode if(!ds_is_from_list()) { xlog("L_ALERT","blocking $rm request from unknown gateway, UA=<$ua>, IP=$si:$sp\n"); exit; } Now, after dispatching a call to some carrier who's gateway address is a FQDN that resolves into multiple IP addresses, when an in-dialog request like BYE or re-Invite from the downstream carriers arrives, ds_is_from_list() returns false and the request gets silently ignored as indicated in the above route block. Is that the expected behavior of ds_is_from_list() function? Thanks, --Sergiu On Wed, Aug 21, 2019 at 6:01 PM Sergiu Pojoga <pojogas@gmail.com<mailto:pojogas@gmail.com>> wrote: Hi ppl, The problem I'm facing is that function ds_is_from_list seems to return false when a gateway's address is a FQDN that resolves into multiple IP addresses (I'm talking about A records), consequently in-dialog requests like BYE and re-Invites get blocked since they don't pass the ds_is_from_list validation. Am I missing some parameter or something? Thanks, --Sergiu _______________________________________________ Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org<mailto:sr-users@lists.kamailio.org> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users -- Henning Westerholt - https://skalatan.de/blog/ Kamailio services - https://skalatan.de/services