#134 Slirp built-in DNS broken by 0.7.3-2

v0.7.x (release)
closed
Henry N.
None
5
2008-08-19
2008-08-11
Paul Rouse
No

The built-in DNS on 10.0.2.3 in slirp appears to have been broken by the update 0.7.3-2 to colinux-slirp-net-daemon.exe to fix bug 1995862 ("udp forwarded packets over slirp have incorrect source ip").

The issue is that the reply packets to the DNS requests now appear to come from the real DNS server, rather than the virtual one on 10.0.2.3.

With the original 0.7.3 release tcpdump gives:
11:44:02.799135 IP 10.0.2.15.32772 > 10.0.2.3.53: 38764+ A? sourceforge.net. (33)
11:44:02.809134 IP 10.0.2.3.53 > 10.0.2.15.32772: 38764 1/0/0 A 216.34.181.60 (49)

With the updated slirp daemon tcpdump shows:
11:49:45.149746 IP 10.0.2.15.32776 > 10.0.2.3.53: 23720+ A? sourceforge.net. (33)
11:49:45.149746 IP 172.21.1.201.53 > 10.0.2.15.32776: 23720 1/0/0 A 216.34.181.60 (49)
11:49:45.149746 IP 10.0.2.15 > 172.21.1.201: ICMP 10.0.2.15 udp port 32776 unreachable, length 85

Surely the original behaviour is what you want in the special case of DNS on 10.0.2.3.

I am using a static configuration for the slirp interface, giving 10.0.2.3 explicitly as the DNS server, and the address 172.21.1.201 is the real DNS server which Windows is using.

Discussion

  • Henry N.

    Henry N. - 2008-08-17
    • assigned_to: nobody --> henryn
     
  • Paul Rouse

    Paul Rouse - 2008-08-18

    Logged In: YES
    user_id=260279
    Originator: YES

    Thank you -- yes, that solves the DNS problem.

    I don't have a test for Bug #1995862 (that was someone else's) so I won't comment on that.

     
  • Henry N.

    Henry N. - 2008-08-19

    Logged In: YES
    user_id=579204
    Originator: NO

    Thanks.
    File colinux-slirp-net-daemon-0.7.3-3.zip is available on SF now.

     
  • Henry N.

    Henry N. - 2008-08-19
    • status: open --> closed
     

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