Hi Isaac, Not all flags are explicitly used elsewhere in the logic of a config; some are used to convey information to modules. In this case: modparam("nathelper", "sipping_bflag", FLB_NATSIPPING) https://kamailio.org/docs/modules/5.1.x/modules/nathelper.html#nathelper.p.… In other words, if this branch flag is set, this Contact will be marked by the nathelper module for periodic pinging via OPTIONS or INFO[1]. The purpose of this periodic server-side pinging is to keep NAT pinholes alive. -- Alex [1] https://kamailio.org/docs/modules/5.1.x/modules/nathelper.html#nathelper.p.… On Thu, Oct 25, 2018 at 07:35:48AM -0700, Isaac wrote: > Hello, > > In the example for a dual-stack IPv6/IPv4 Kamailio setup here: https://kb.asipto.com/kamailio:kamailio-mixed-ipv4-ipv6 the "FLB_IPV6" flag is being sent on IPv6 registrations. Why set this flag on IPv6 registrations? If I understand correctly, registration requests never make it beyond !save("location so it's not like the flag can be used further in the dial-plan. > > The code in question: > > route[REGISTRAR] { > if (is_method("REGISTER")) > { > if(isflagset(FLT_NATS)) > { > setbflag(FLB_NATB); > # uncomment next line to do SIP NAT pinging > ## setbflag(FLB_NATSIPPING); > } > if(af==INET6) > setbflag(FLB_IPV6); > if (!save("location")) > sl_reply_error(); > exit; > } > } > > > Any help is appreciated. > > Thanks > > > _______________________________________________ > Kamailio (SER) - Users Mailing List > sr-users(a)lists.kamailio.org > https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users