Did any one had any problem with this? I have a test setup where I have the following directives for dns caching: use_dns_cache=yes #enabling DNS caching dns_cache_del_nonexp=yes # deletes entries if the memory is becoming full dns_cache_flags=0 dns_cache_gc_interval=120 dns_cache_init=on dns_cache_max_ttl=3600 dns_try_ipv6=no # yes if you want the lookup to be for IPv6 also dns_try_naptr=yes despite the fact that I have *dns_try_ipv6=no* kamailio sends a AAAA request to the DNS server. This is an extra request in a case where it seems not to be needed. Also, it seems that a NAPTR request is not sent - I need to investigate more, being just a hunch for now. All the best Radu Costin