Re: [sr-dev] dns resolver issue (RFC3263)

Dear Klaus et al.

Exactly the same was in my mind. So my plan is to sort the protocols using these dns_PROTO_pref values. If the pref is the same to all protocols, (like it should according to the RFC3263 dns lookup process) then the order will be udp,tcp,tls,sctp.

Any other suggestions are welcome!

Thanks, Misi

On 2012-11-05 15:03, Klaus Darilion wrote:

Indeed, this is not implemented correctly.

If you fix it, the question is: what should be used if there are SRV records for UDP and TCP?

AFAIK there is already a configuration option to choose the respective NAPTR records according to local priority. These config options could be reused.

See dns_udp_pref/dns_tcp_pref/... options in doc/dns.txt

regards Klaus

On 29.10.2012 16:33, MÉSZÁROS Mihály wrote:

...

Hi All,

I am experiencing an issue when i try to contact xy@cisco.com. I found that kamailio/sip-router can't resolve by default resolving way a TCP + SRV records from domain cisco.com.

e.g. cisco.com

misi@alma:~$ host -t NAPTR cisco.com
cisco.com has no NAPTR record
misi@alma:~$ host -t SRV _sip._udp.cisco.com
Host _sip._udp.cisco.com not found: 3(NXDOMAIN)
misi@alma:~$ host -t SRV _sip._tcp.cisco.com
_sip._tcp.cisco.com has SRV record 1 0 5060 vcsgw.cisco.com.
misi@alma:~$ host -t SRV _sips._tcp.cisco.com
_sips._tcp.cisco.com has SRV record 1 0 5061 vcsgw.cisco.com.

I can't call xy@cisco.com because it does not exists an NAPTR record in domain cisco.com, and furthermore no SRV with udp.

But it exists sip+tcp record and also exists an secure sip SRV, so sips+tcp record!

I read rfc3263 I find kamailio dns resolver is not working as it should according RFC3263.

http://tools.ietf.org/html/rfc3263

_If no NAPTR records are found, the client constructs SRV queries
for those transport protocols it supports, and does a query for 

each._

So kamailio should query all (udp, tcp, tls, sctp whatever) protocols.

Can anyone help/guide me to create a fix to this issue? My plan is to create a patch to kamailio resolver, to correct and behave according RFC3263.

Any help or guidance appreciated!

Thanks, Misi

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