Re: Windows interfaces GUIDs issue caused reverse DNS resolution to fail

[Daniel Miller <bonsaiviking () gmail com>]

Robert,

Thanks so much for the analysis! We had seen reports of this error, but had
not been able to narrow it down to a cause. I'll verify and apply your fix
right away.

Dan

On Nov 24, 2016 1:07 AM, "Robert Croteau" <robert.croteau () quest com> wrote:

> Hi all,
>
>
>
> I installed the windows version of 7.31 on Windows Server 2016 and I
> couldn’t get the reverse DNS hostname in the results.
>
> The following message:
>
>
>
>     “mass_dns: warning: Unable to determine any DNS servers. Reverse DNS
> is disabled. Try using --system-dns or specify valid servers with
> --dns-servers”
>
>
>
> appeared in the output.  I could also get the following message if I
> installed winpcap first then installed nmap (with npcap):
>
>
>
>     “Interface XXXXXXX is not known; ignoring its nameservers.”
>
>
>
> It seems the following code is the culprit:
>
>
>
> nmap_dns.cc :940
>
> if (strcmp(guid, pcap_guid) == 0)
>
>     return true;
>
>
>
> should be changed to
>
>
>
> if (strcasecmp(guid, pcap_guid) == 0)
>
>     return true;
>
>
>
> The issue seems to be that an interface GUID in HKEY_LOCAL_MACHINE\SYSTEM\
> CurrentControlSet\services\Tcpip\Parameters\Interfaces can either be
> defined in uppercase or lowercase but internally to nmap (from npcap?) the
> interface list is saved as uppercase.  So in my case, my interfaces were
> lowercase and did not match the interfaces from the  list returned by
> getinterfaces() in interface_is_known_by_guid().
>
>
>
> Using strcasecmp() instead of strcmp() solved the problem.
>
> Hope this helps.
>
>
>
> Thanks
>
>
>
> *Robert-André Croteau*
>
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