[Serdev] bug in DNS cache resolver?

[Alfred E. Heggestad]

hi

I found some strange behavior in SER 0.10 when proxying requests
to other domains.. The SRV lookup is done but one of the following
A lookups contains a bogus query:


   6   0.190355 208.68.208.201 -> 208.68.208.201 DNS Standard query SRV _sip._udp.oplug.org
   7   0.190842 208.68.208.201 -> 208.68.208.201 DNS Standard query response SRV 0 0 5060 sip.symbianos.org
   8   0.191245 208.68.208.201 -> 208.68.208.201 DNS Standard query A sip.symbianos.org
  11   0.336608 208.68.208.201 -> 208.68.208.201 DNS Standard query response CNAME kursk.symbianos.org A 212.13.202.25
  12   0.337432 208.68.208.201 -> 208.68.208.201 DNS Standard query A \r\312\031.creytiv.com
  13   0.337714 208.68.208.201 -> 208.68.208.201 DNS Standard query response, No such name
  14   0.337902 208.68.208.201 -> 208.68.208.201 DNS Standard query A \r\312\031
  15   0.338078 208.68.208.201 -> 208.68.208.201 DNS Standard query response, No such name
  16   0.338244 208.68.208.201 -> 208.68.208.201 DNS Standard query A oplug.org
  17   0.338381 208.68.208.201 -> 208.68.208.201 DNS Standard query response A 195.159.98.118
  18   0.339271 208.68.208.201 -> 195.159.98.118 SIP/SDP Request: INVITE sip:slay at oplug.org, with session description
  19   0.788264 208.68.208.201 -> 195.159.98.118 SIP/SDP Request: INVITE sip:slay at oplug.org, with session description
  20   1.788138 208.68.208.201 -> 195.159.98.118 SIP/SDP Request: INVITE sip:slay at oplug.org, with session description
  21   3.788158 208.68.208.201 -> 195.159.98.118 SIP/SDP Request: INVITE sip:slay at oplug.org, with session description
  22   7.115991 208.68.208.201 -> 84.209.226.67 UDP Source port: sip  Destination port: 5062
  23   7.804260 208.68.208.201 -> 195.159.98.118 SIP/SDP Request: INVITE sip:slay at oplug.org, with session description


(some packets removed)


as you can see, packet #11 returns the correct IP address where the
request should be sent to.


packets #12 and #14 contains a bogus query, resulting in no answers. finally
SER resolves the A records of "oplug.org" which gives back "195.159.98.118"
and this is where the request is sent. however, there is no SIP server there..

the request should have been relayed to "212.13.202.25"


However, if I disable local DNS caching in SER (use_dns_cache=off) then SRV lookups
are working fine.


I have the complete trace if needed.


/alfred