NAPTR/SRV lookups fail when use_dns_failover is enabled.

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Jeremy Gadd

19 Jan 2017 19 Jan '17

10:58 p.m.

Hello, everyone! I'm trying to enable dns_srv_lb but I'm stuck just before I can get there. If I don't enable use_dns_failover, lookups work and calls route but always to the first host. We need to load balance, so that doesn't work very well. If I enable use_dns_failover, the lookups stop working completely and we get a dns lookup failure like so: ERROR: tm [ut.h:296]: uri2dst2(): ERROR: uri2dst: failed to resolve " redacted.hostname.here.com" :unresolvable A or AAAA request (-7) This works: use_dns_cache=on dns_use_search_list=no dns_try_naptr=on # use_dns_failover=on This breaks it: use_dns_cache=on dns_use_search_list=no dns_try_naptr=on use_dns_failover=on I have checked to see that use_dns_failover is compiled in: version: kamailio 4.4.2 (x86_64/linux) flags: STATS: Off, USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, USE_RAW_SOCKS, DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MEM, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX, FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR, USE_DST_BLACKLIST, HAVE_RESOLV_RES ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144, MAX_LISTEN 16, MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB poll method support: poll, epoll_lt, epoll_et, sigio_rt, select. id: unknown compiled with gcc 4.9.2

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Carsten Bock

20 Jan 20 Jan

8:37 a.m.

New subject: NAPTR/SRV lookups fail when use_dns_failover is enabled.

Hi, we have the following settings and those work fine for us (Kamailio 4 and later): # Do SRV-Loadbalancing: dns_srv_lb=yes # Always prefer IPv6: dns_try_ipv6=yes # DNS-Based failover use_dns_failover=yes # Query NAPTR-Records as well (we use NAPTR, so the client can detect the outbound Proxy (P-CSCF), but internally we only use only SRV-records) dns_try_naptr=no Sounds to me, like a DNS problem, not a Kamailio problem. In our DNS Zone, we have the following, for example: wt 1D IN A 84.46.93.82 wt 1D IN A 84.46.93.84 wt-1 1D IN A 84.46.93.82 wt-2 1D IN A 84.46.93.84 wt 1D IN NAPTR 10 10 "s" "SIP+D2U" "" _sip._udp.wt _sip._udp.wt 1D SRV 10 1 5060 wt-1 _sip._udp.wt 1D SRV 20 1 5060 wt-2 On Debian/Ubuntu, you can verify this with Sofia-SIP (apt-get install sofia-sip-bin): carsten@carsten-HP-EliteBook-840-G3:~$ sip-dig wt.ng-voice.com 1 1.000 udp 5060 84.46.93.82 2 1.000 udp 5060 84.46.93.84 Thanks, Carsten 2017-01-19 22:58 GMT+01:00 Jeremy Gadd <jeremygadd(a)gmail.com>om>:

...

Hello, everyone! I'm trying to enable dns_srv_lb but I'm stuck just before I can get there. If I don't enable use_dns_failover, lookups work and calls route but always to the first host. We need to load balance, so that doesn't work very well. If I enable use_dns_failover, the lookups stop working completely and we get a dns lookup failure like so: ERROR: tm [ut.h:296]: uri2dst2(): ERROR: uri2dst: failed to resolve "redacted.hostname.here.com" :unresolvable A or AAAA request (-7) This works: use_dns_cache=on dns_use_search_list=no dns_try_naptr=on # use_dns_failover=on This breaks it: use_dns_cache=on dns_use_search_list=no dns_try_naptr=on use_dns_failover=on I have checked to see that use_dns_failover is compiled in: version: kamailio 4.4.2 (x86_64/linux) flags: STATS: Off, USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, USE_RAW_SOCKS, DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MEM, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX, FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR, USE_DST_BLACKLIST, HAVE_RESOLV_RES ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144, MAX_LISTEN 16, MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB poll method support: poll, epoll_lt, epoll_et, sigio_rt, select. id: unknown compiled with gcc 4.9.2 _______________________________________________ SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users(a)lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users

Jeremy Gadd

5:47 p.m.

New subject: NAPTR/SRV lookups fail when use_dns_failover is enabled.

Thanks for the response! DNS lookups work in Kamailio as long as use_dns_failover is set to "off." It's only when the failover is enabled that they break. I think this means it's not a DNS issue, but something in Kamailio. I should mention we're pointing to Verizon's services with many many thousands of customers, so it's unlikely to be misconfigured DNS (unless it's something local that only breaks when use_dns_failover is enabled?) On Fri, Jan 20, 2017 at 12:37 AM, Carsten Bock <carsten(a)ng-voice.com> wrote:

...

Hello, everyone! I'm trying to enable dns_srv_lb but I'm stuck just before I can get

there.

If I don't enable use_dns_failover, lookups work and calls route but

always

to the first host. We need to load balance, so that doesn't work very

well.

If I enable use_dns_failover, the lookups stop working completely and we

get

a dns lookup failure like so: ERROR: tm [ut.h:296]: uri2dst2(): ERROR: uri2dst: failed to resolve "redacted.hostname.here.com" :unresolvable A or AAAA request (-7) This works: use_dns_cache=on dns_use_search_list=no dns_try_naptr=on # use_dns_failover=on This breaks it: use_dns_cache=on dns_use_search_list=no dns_try_naptr=on use_dns_failover=on I have checked to see that use_dns_failover is compiled in: version: kamailio 4.4.2 (x86_64/linux) flags: STATS: Off, USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, USE_RAW_SOCKS, DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MEM, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX, FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR, USE_DST_BLACKLIST, HAVE_RESOLV_RES ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144, MAX_LISTEN 16, MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB poll method support: poll, epoll_lt, epoll_et, sigio_rt, select. id: unknown compiled with gcc 4.9.2 _______________________________________________ SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users(a)lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users

-- Carsten Bock CEO (Geschäftsführer) ng-voice GmbH Millerntorplatz 1 20359 Hamburg / Germany http://www.ng-voice.com mailto:carsten@ng-voice.com Office +49 40 5247593-40 Fax +49 40 5247593-99 Sitz der Gesellschaft: Hamburg Registergericht: Amtsgericht Hamburg, HRB 120189 Geschäftsführer: Carsten Bock Ust-ID: DE279344284 Hier finden Sie unsere handelsrechtlichen Pflichtangaben: http://www.ng-voice.com/imprint/ _______________________________________________ SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users(a)lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users

Carsten Bock

23 Jan 23 Jan

8:45 a.m.

New subject: NAPTR/SRV lookups fail when use_dns_failover is enabled.

Hi, can you try the sip-dig command on that particular domain? If you set that domain in script or from a module (e.g. Dispatcher), don't set a port. According to RFC 3263, the DNS-records are treated differently, if no port is set (e.g. "redacted.hostname.here.com:5060" will produce a different result than "redacted.hostname.here.com"). I've checked the compliance of Kamailio with RFC 3263 in the past, as DNS-Failover is mandatory for IMS. I would find it rather strange, if it should work correct in all of our deployments and not in yours. Thanks, Carsten 2017-01-20 17:47 GMT+01:00 Jeremy Gadd <jeremygadd(a)gmail.com>om>:

...

Hello, everyone! I'm trying to enable dns_srv_lb but I'm stuck just before I can get there. If I don't enable use_dns_failover, lookups work and calls route but always to the first host. We need to load balance, so that doesn't work very well. If I enable use_dns_failover, the lookups stop working completely and we get a dns lookup failure like so: ERROR: tm [ut.h:296]: uri2dst2(): ERROR: uri2dst: failed to resolve "redacted.hostname.here.com" :unresolvable A or AAAA request (-7) This works: use_dns_cache=on dns_use_search_list=no dns_try_naptr=on # use_dns_failover=on This breaks it: use_dns_cache=on dns_use_search_list=no dns_try_naptr=on use_dns_failover=on I have checked to see that use_dns_failover is compiled in: version: kamailio 4.4.2 (x86_64/linux) flags: STATS: Off, USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, USE_RAW_SOCKS, DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MEM, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX, FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR, USE_DST_BLACKLIST, HAVE_RESOLV_RES ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144, MAX_LISTEN 16, MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB poll method support: poll, epoll_lt, epoll_et, sigio_rt, select. id: unknown compiled with gcc 4.9.2 _______________________________________________ SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users(a)lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users

_______________________________________________ SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users(a)lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users

Jeremy Gadd

10:49 p.m.

New subject: NAPTR/SRV lookups fail when use_dns_failover is enabled.

It was the port in the LCR table! You're the man! Thanks so much for your help. On Mon, Jan 23, 2017 at 12:45 AM, Carsten Bock <carsten(a)ng-voice.com> wrote:

...

Thanks for the response! DNS lookups work in Kamailio as long as use_dns_failover is set to "off." It's only when the failover is enabled that they break. I think this

means

it's not a DNS issue, but something in Kamailio. I should mention we're pointing to Verizon's services with many many thousands of customers, so it's unlikely to be misconfigured DNS (unless it's something local that only breaks when use_dns_failover is enabled?) On Fri, Jan 20, 2017 at 12:37 AM, Carsten Bock <carsten(a)ng-voice.com>

wrote:

> > Hi, > > we have the following settings and those work fine for us (Kamailio 4 > and later): > > # Do SRV-Loadbalancing: > dns_srv_lb=yes > # Always prefer IPv6: > dns_try_ipv6=yes > # DNS-Based failover > use_dns_failover=yes > # Query NAPTR-Records as well (we use NAPTR, so the client can detect > the outbound Proxy (P-CSCF), but internally we only use only > SRV-records) > dns_try_naptr=no > > Sounds to me, like a DNS problem, not a Kamailio problem. > > In our DNS Zone, we have the following, for example: > > wt 1D IN A 84.46.93.82 > wt 1D IN A 84.46.93.84 > wt-1 1D IN A 84.46.93.82 > wt-2 1D IN A 84.46.93.84 > wt 1D IN NAPTR 10 10 "s" "SIP+D2U" "" > _sip._udp.wt > > _sip._udp.wt 1D SRV 10 1 5060 wt-1 > _sip._udp.wt 1D SRV 20 1 5060 wt-2 > > On Debian/Ubuntu, you can verify this with Sofia-SIP (apt-get install > sofia-sip-bin): > > carsten@carsten-HP-EliteBook-840-G3:~$ sip-dig wt.ng-voice.com > 1 1.000 udp 5060 84.46.93.82 > 2 1.000 udp 5060 84.46.93.84 > > Thanks, > Carsten > > > 2017-01-19 22:58 GMT+01:00 Jeremy Gadd <jeremygadd(a)gmail.com>om>: > > Hello, everyone! > > > > I'm trying to enable dns_srv_lb but I'm stuck just before I can get > > there. > > If I don't enable use_dns_failover, lookups work and calls route but > > always > > to the first host. We need to load balance, so that doesn't work very > > well. > > > > If I enable use_dns_failover, the lookups stop working completely and

> > get > > a dns lookup failure like so: > > ERROR: tm [ut.h:296]: uri2dst2(): ERROR: uri2dst: failed to resolve > > "redacted.hostname.here.com" :unresolvable A or AAAA request (-7) > > > > This works: > > use_dns_cache=on > > dns_use_search_list=no > > dns_try_naptr=on > > # use_dns_failover=on > > > > This breaks it: > > use_dns_cache=on > > dns_use_search_list=no > > dns_try_naptr=on > > use_dns_failover=on > > > > I have checked to see that use_dns_failover is compiled in: > > version: kamailio 4.4.2 (x86_64/linux) > > flags: STATS: Off, USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS,

USE_RAW_SOCKS,

> > DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MEM, SHM_MMAP, PKG_MALLOC, > > Q_MALLOC, F_MALLOC, TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX, > > FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR, > > USE_DST_BLACKLIST, HAVE_RESOLV_RES > > ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144, MAX_LISTEN 16, > > MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB > > poll method support: poll, epoll_lt, epoll_et, sigio_rt, select. > > id: unknown > > compiled with gcc 4.9.2 > > > > _______________________________________________ > > SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing

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Carsten Bock
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