Re: Cygwin unable to resolve hostnames

[Jan Bruun Andersen <jan_bruun_andersen@jabba.dk>]

The only thing in that list of interfaces that have IP is the
"Ethernet adapter Ethernet0". Right of my head I don't see anything
obviously wrong. My first suggestion would be to disable IPv6 on the
adapter, just on the odd chance that it is the cause.

After that I would start ping'ing the default gateway by IP-address
(192.168.244.2). This also happens to be where your DNS lives, so that
will test 2 issues in one go.

Jan Bruun Andersen


On 11 December 2015 at 11:18, Carl-Erik Kopseng <carlerik@gmail.com> wrote:
>> > I'm not sure when this started, but recently Cygwin has been unable to
>> > resolve (certain) hostnames.
>> >
>> > Example:
>> >  wget github.com
>> > --2015-07-22 15:17:04--  http://github.com/
>> > Resolving github.com (github.com)... failed: Non-recoverable failure
>> > in name resolution.
> [snip]
>
> I have the same problem and I have just made a clean Cygwin64 install
> on a computer that has never had Cygwin installed before. I have not
> messed with any settings, yet I also cannot use curl or git to access
> almost any site. Only the built-in Windows CLI  tools, such as `ping`,
> works.
>
>> > Any ideas?
>>
>> Cygwin by default uses the same resolution as Windows, that means that
>> you have something in Cygwin's configuration that affects resolution.
>> First and most obvious is /etc/resolv.conf; by default I don't think
>> there is one, but you can create it and Cygwin will use it.
>
> Pointers on what to actually put in that file?
>
>> Next would be if you have more than one DNS resolver in your (Windows)
>> network configuration, this means that any one of them can be used at
>> any time (literally it should be random)... and by coincidence Cygwin is
>> using one that doesn't work, the Web browser is using another, and
>> things change with different tests. Run 'ipconfig -all' and see under
>> the network adapter what's listed for "DNS Servers".
>>
>> Also if there is more than one network adapter something similar to the
>> last paragraph will happen. I would think that Cygwin uses the DNS
>> servers on the "default" adapter.
>
> I am guessing my problems have something to do with this part, as I am
> running Windows 8.1 in VMWare. VMWare adds lots of weird network stuff,
> all of which I am not too familiar with ...
>
> The below output is from `ipconfig /all`. Could any of the info be put
> in the aforementioned resolv.conf file?
>
>
> Windows IP Configuration
>
>    Host Name . . . . . . . . . . . . : macbookpro
>    Primary Dns Suffix  . . . . . . . :
>    Node Type . . . . . . . . . . . . : Hybrid
>    IP Routing Enabled. . . . . . . . : No
>    WINS Proxy Enabled. . . . . . . . : No
>    DNS Suffix Search List. . . . . . : localdomain
>
> Ethernet adapter Bluetooth Network Connection 2:
>
>    Media State . . . . . . . . . . . : Media disconnected
>    Connection-specific DNS Suffix  . :
>    Description . . . . . . . . . . . : Bluetooth Device (Personal Area
> Network) #2
>    Physical Address. . . . . . . . . : 00-50-56-E2-FB-E9
>    DHCP Enabled. . . . . . . . . . . : Yes
>    Autoconfiguration Enabled . . . . : Yes
>
> Ethernet adapter Ethernet0:
>
>    Connection-specific DNS Suffix  . : localdomain
>    Description . . . . . . . . . . . : Intel(R) 82574L Gigabit Network
> Connection
>    Physical Address. . . . . . . . . : 00-0C-29-6A-39-52
>    DHCP Enabled. . . . . . . . . . . : Yes
>    Autoconfiguration Enabled . . . . : Yes
>    Link-local IPv6 Address . . . . . : fe80::20b9:f45e:9310:3f4a%9(Preferred)
>    IPv4 Address. . . . . . . . . . . : 192.168.244.145(Preferred)
>    Subnet Mask . . . . . . . . . . . : 255.255.255.0
>    Lease Obtained. . . . . . . . . . : Friday, December 11, 2015 10:59:56
>    Lease Expires . . . . . . . . . . : Friday, December 11, 2015 11:29:56
>    Default Gateway . . . . . . . . . : 192.168.244.2
>    DHCP Server . . . . . . . . . . . : 192.168.244.254
>    DHCPv6 IAID . . . . . . . . . . . : 167775273
>    DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-1A-89-39-FB-14-10-9F-E1-7B-95
>    DNS Servers . . . . . . . . . . . : 192.168.244.2
>    Primary WINS Server . . . . . . . : 192.168.244.2
>    NetBIOS over Tcpip. . . . . . . . : Enabled
>
> Tunnel adapter Teredo Tunneling Pseudo-Interface:
>
>    Connection-specific DNS Suffix  . :
>    Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
>    Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
>    DHCP Enabled. . . . . . . . . . . : No
>    Autoconfiguration Enabled . . . . : Yes
>    IPv6 Address. . . . . . . . . . . :
> 2001:0:5ef5:79fb:867:2876:3f57:b6e(Preferred)
>    Link-local IPv6 Address . . . . . : fe80::867:2876:3f57:b6e%7(Preferred)
>    Default Gateway . . . . . . . . . : ::
>    DHCPv6 IAID . . . . . . . . . . . : 218103808
>    DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-1A-89-39-FB-14-10-9F-E1-7B-95
>    NetBIOS over Tcpip. . . . . . . . : Disabled
>
> Tunnel adapter isatap.localdomain:
>
>    Media State . . . . . . . . . . . : Media disconnected
>    Connection-specific DNS Suffix  . : localdomain
>    Description . . . . . . . . . . . : Microsoft ISATAP Adapter #2
>    Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
>    DHCP Enabled. . . . . . . . . . . : No
>    Autoconfiguration Enabled . . . . : Yes
>
>
> Regards
> Carl-Erik Kopseng
>
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