Nmap Development mailing list archives
Windows interfaces GUIDs issue caused reverse DNS resolution to fail
From: Robert Croteau <robert.croteau () quest com>
Date: Thu, 24 Nov 2016 07:06:57 +0000
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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Current thread:
- Windows interfaces GUIDs issue caused reverse DNS resolution to fail Robert Croteau (Nov 23)
- Re: Windows interfaces GUIDs issue caused reverse DNS resolution to fail Daniel Miller (Nov 27)