[avahi] Strange MDNS response from Axis cameras

[Sebastien Estienne]

On 2/7/06, Iván Sánchez Ortega <i.sanchez at mirame.net> wrote:
> Hi there,
>
> As this is my first message to this mailing list, I might as well introduce
> myself briefly. I'm Iván Sánchez, from Spain. Linux junkie, PHP programmer,
> Computer Science student. Quite some experience with webservers and IP
> networking, near-zero experience with Avahi and MDNS.
>
>
> The fact is, I'm currently working with some Axis IP cameras [1]. Wonderful
> gadgets, they've got a 100Mhz µprocessor running Linux, featuring a webserver
> and some uPnP/zeroconf support. My goal is to detect a large number of these
> cameras in a large network, by using avahi.
> [1] http://www.axis.com/products/video/camera/
>
>
> However, I'm running into some problems. One of the cameras is returning a
> "strange" MDNS response, pointing to a non-existant IP address. I managed to
> capture that response with ethereal (my workstation is 01:00:5e:xx:xx:xx, the
> camera is 00:40:8c:xx:xx:xx at 192.168.2.81):
>
>
>
> Frame 339 (354 bytes on wire, 354 bytes captured)
> Ethernet II, Src: 192.168.2.81 (00:40:8c:xx:xx:xx), Dst: 01:00:5e:xx:xx:xx
> (01:00:5e:xx:xx:xx)
> Internet Protocol, Src: axis-00408cxxxxxx.local (192.168.2.81), Dst:
> 224.0.0.251 (224.0.0.251)
> User Datagram Protocol, Src Port: 5353 (5353), Dst Port: 5353 (5353)
> Domain Name System (response)
>     Transaction ID: 0x0000
>     Flags: 0x8400 (Standard query response, No error)
>     Questions: 0
>     Answer RRs: 8
>     Authority RRs: 0
>     Additional RRs: 0
>     Answers
>         axis-00408cxxxxxx.local: type A, class IN, addr 192.168.2.81
>         axis-00408cxxxxxx.local: type A, class FLUSH, addr 169.254.154.134
>         AXIS 213 - 00408CXXXXXX._http._tcp.local: type SRV, class FLUSH,
> priority 0, weight 0, port 80, target axis-00408cxxxxxx.local
>         AXIS 213 - 00408CXXXXXX._http._tcp.local: type TXT, class FLUSH
>         AXIS 213 - 00408CXXXXXX._axis-video._tcp.local: type SRV, class FLUSH,
> priority 0, weight 0, port 80, target axis-00408cxxxxxx.local
>         AXIS 213 - 00408CXXXXXX._axis-video._tcp.local: type TXT, class FLUSH
>         AXIS 213 - 00408CXXXXXX._rtsp._tcp.local: type SRV, class FLUSH,
> priority 0, weight 0, port 554, target axis-00408cxxxxxx.local
>         AXIS 213 - 00408CXXXXXX._rtsp._tcp.local: type TXT, class FLUSH
>
>
> This translates to:
>
> ivan at silverspark:~$ avahi-browse -acr
> [...snip...]
> = eth0 IPv4 AXIS 213 - 00408CXXXXXX               Web Site             local
>    hostname = [axis-00408cxxxxxx.local]
>    address = [169.254.154.134]
>    port = [80]
>    txt = []
>
>
>
> So, it seems that the camera is returning two addresses: the "real" address
> (192.168.2.81), and an ad-hoc zeroconf address (169.254.154.134). Avahi gets
> the non-existant, non-working ad-hoc address, while windoze's uPnP gets the
> "real", good address. I haven't tried with Apple's Zeroconf.
>
>
> So, questions:
>
> Avahi doesn't get the correct IP address from this camera. Who is to blame for
> this: Axis' implementation of MDNS responses, or Avahi's bad interpretation
> of it?

does "avahi-resolve-host-name axis-00408cxxxxxx.local" returns the
link local ip?

you could try setting a link local address on your host as an alias ip.

>
> The cameras publish the _axis-video and _rtsp services. However, applications
> (such as the zeroconf:/ kioslave aren't aware of these services and ignore
> them. What would be the way to do this?

support for these services could be easily added to zeroconf kioslave
if you know about a kde application that can handle the datas

>
>
>
> Thanks for reading all this,
> --
> ----------------------------------
> Iván Sánchez Ortega <i.sanchez at mirame.net> <ivansanchez at escomposlinux.org>
>
> "I loathed every day and regret every day I spent in school.  I like to be
> taught to read and write and add and then be left alone."
>  -    Woody Allen
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>


--
Sebastien Estienne