[Dnsmasq-discuss] Wrong server IP in dual normal/proxyDHCP mode

Simon Kelley simon at thekelleys.org.uk
Tue May 19 23:04:35 BST 2015 

Hi Alkis,

I just pushed a patch into git

http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=7f8565b94ca52dde31f7688a9f9a0cc611d9dae3

Please could you see if that helps? It should apply to the Ubuntu 14.04
version, if that's easier.

Cheers,

Simon.







On 16/05/15 10:19, Alkis Georgopoulos wrote:
> OK, I managed to pinpoint the difference using another tcpdump command
> line (-XX):
> $ sudo tcpdump -i eth1 port 67 or port 68 or port 69 or port 4011 -e -n
> -vv -XX
> 
> 
> 1) Without the normal dhcp-range, so that the client boots successfully:
> 
> 11:51:23.036199 c0:4a:00:02:bc:1e > 3c:07:71:a2:02:e3, ethertype IPv4
> (0x0800), length 342: (tos 0xc0, ttl 64, id 27064, offset 0, flags
> [none], proto UDP (17), length 328)
>     10.161.254.11.4011 > 10.161.254.149.4011: [udp sum ok] UDP, length 300
>   0x0000:  3c07 71a2 02e3 c04a 0002 bc1e 0800 45c0  <.q....J......E.
>   0x0010:  0148 69b8 0000 4011 fd49 0aa1 fe0b 0aa1  .Hi... at ..I......
>   0x0020:  fe95 0fab 0fab 0134 7a4c 0201 0600 72a2  .......4zL....r.
>   0x0030:  02e3 0004 0000 0000 0000 0aa1 fe95 c0a8  ................
>   0x0040:  4401 0000 0000 3c07 71a2 02e3 0000 0000  D.....<.q.......
>   0x0050:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x0060:  0000 0000 0000 0000 0000 0000 0000 0000  ...............http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=7f8565b94ca52dde31f7688a9f9a0cc611d9dae3.
>   0x0070:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x0080:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x0090:  0000 0000 0000 6c74 7370 2f69 3338 362f  ......ltsp/i386/
>   0x00a0:  7078 656c 696e 7578 2e30 0000 0000 0000  pxelinux.0......
>   0x00b0:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x00c0:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x00d0:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x00e0:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x00f0:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x0100:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x0110:  0000 0000 0000 6382 5363 3501 0536 04c0  ......c.Sc5..6..
>   0x0120:  a844 013c 0950 5845 436c 6965 6e74 6111  .D.<.PXEClientahttp://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=7f8565b94ca52dde31f7688a9f9a0cc611d9dae3.
>   0x0130:  0050 48dc b1ba 8ae2 11a0 0d3c 0771 a202  .PH........<.q..
>   0x0140:  e32b 0747 0480 0000 00ff ff00 0000 0000  .+.G............
>   0x0150:  0000 0000 0000                           ......
> 
> 
> 2) Including the normal dhcp-range, so that the client fails:
> 
> 11:54:45.038754 c0:4a:00:02:bc:1e > 3c:07:71:a2:02:e3, ethertype IPv4
> (0x0800), length 342: (tos 0xc0, ttl 64, id 57382, offset 0, flags
> [none], proto UDP (17), length 328)
>     10.161.254.11.4011 > 10.161.254.149.4011: [udp sum ok] UDP, length 300
>   0x0000:  3c07 71a2 02e3 c04a 0002 bc1e 0800 45c0  <.q....J......E.
>   0x0010:  0148 e026 0000 4011 86db 0aa1 fe0b 0aa1  .H.&.. at .........
>   0x0020:  fe95 0fab 0fab 0134 7345 0201 0600 72a2  .......4sE....r.
>   0x0030:  02e3 0004 0000 0000 0000 0aa1 fe95 0aa1  ................
>   0x0040:  fe0b 0000 0000 3c07 71a2 02e3 0000 0000  ......<.q.......
>   0x0050:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x0060:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x0070:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x0080:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x0090:  0000 0000 0000 6c74 7370 2f69 3338 362f  ......ltsp/i386/
>   0x00a0:  7078 656c 696e 7578 2e30 0000 0000 0000  pxelinux.0......
>   0x00b0:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x00c0:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x00d0:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x00e0:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x00f0:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x0100:  0000 0000 0000 0000 0000 0000 0000 0000  ................
>   0x0110:  0000 0000 0000 6382 5363 3501 0536 040a  ......c.Sc5..6..
>   0x0120:  a1fe 0b3c 0950 5845 436c 6965 6e74 6111  ...<.PXEClienta.
>   0x0130:  0050 48dc b1ba 8ae2 11a0 0d3c 0771 a202  .PH........<.q..
>   0x0140:  e32b 0747 0480 0000 00ff ff00 0000 0000  .+.G..........http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=7f8565b94ca52dde31f7688a9f9a0cc611d9dae3..
>   0x0150:  0000 0000 0000                           ......
> 
> 
> Search for 192.168.68.1 (=c0.a8.44.01) in the first message, it exists
> in 2 offsets, while in the second (=correct) packet it doesn't.
> 
> Sorry I couldn't find out how to tell tcpdump or wireshark to decode
> that particular packet, wireshark just mentions it's a UDP protocol at
> altserviceboot (4011) port.
> 
> _______________________________________________
> Dnsmasq-discuss mailing list
> Dnsmasq-discuss at lists.thekelleys.org.uk
> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
>

More information about the Dnsmasq-discuss mailing list