1

I have a Kali Linux installed in VMWare Workstation. The virtual machines is configured for using NAT. The host server is Windows 8.1.

DNS in Kali is not working:

$ ping -c1 www.google.es
ping: unknown host www.google.es

Networking is working:

$ ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_req=1 ttl=128 time=32.0 ms
64 bytes from 8.8.8.8: icmp_req=2 ttl=128 time=25.0 ms

DNSs configured are Google's:

$ cat /etc/resolv.conf
nameserver 8.8.8.8
nameserver 8.8.8.9

Any idea?

  • 2
    What does sudo dhclient -v wlan0 (substitue wlan0 for your interface) say? And dig google.com? – agtoever Jan 29 '15 at 11:14
1

There are two possible points of failure:

  • is TCP/UDP connectivity to the DNS server working?
  • is the C library configured to use DNS in the first place, and if so, using which resolver library?

The first point can be tested using any of the commands suggested before:

host www.google.es 8.8.8.8
nslookup www.google.es 8.8.8.8
dig +short www.google.es @8.8.8.8

Since the DNS server can be pinged successfully, we know IP routing works and ICMP traffic is allowed - but it tells us nothing about DNS traffic specifically, i.e. TCP and UDP traffic to port 53. A firewall could block that without blocking ICMP, or vice versa.

For the second possible point of failure, run:

grep hosts /etc/nsswitch.conf

If the answer does not include keywords dns, resolve nor lwres, then the hostname resolution in this VM has been configured to not use DNS at all - the keywords will indicate which methods are actually going to be used.

  • dns is the classic DNS resolver, configured via /etc/resolv.conf
  • lwres is libnss-lwres: if you find this, also verify that a lwresd process is running and it has not been configured to use a custom configuration file instead of the default /etc/resolv.conf
  • resolve indicates libnss-resolve: if you find this, verify that the systemd-resolved process is running, and use the systemd-resolve --status command to view the current DNS configuration. In this case the classic /etc/resolv.conf might not necessarily be used at all, other than to direct applications that use their own DNS resolver libraries to send their queries to systemd-resolved.

To test whether or not an application can successfully use whichever hostname resolution library has been configured, use getent hosts www.google.es. If you think the application uses IPv4 only, or specifies a preference for IPv4, you can also test with getent ahostsv4 www.google.es. Likewise, to test specifically for IPv6 only, you can use getent ahostsv6 www.google.es.

0

Try to use host or nslookup and force it to ask a special server

$ host www.google.es 8.8.8.8
$ nslookup www.google.es 8.8.8.8
0

Or, dig www.google.es @8.8.8.8 Try other hostnames as well.

There may be needed to check if DNS port 53 is open (mostly UDP, but TCP as well )

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.