Getting DHCP-assigned static IP hostnames to resolve in home network

Question

Hi,

I am new to Sophos/Astaro and working on configuring Sophos Home UTM
for the first time on my home network.  So far, I am successfully using the
DHCP server to assign static IP addresses to most devices based on
their MAC addresses, with a handful of dynamic IP addresses set aside
for guest devices.  But there's one aspect of it that isn't working
the way I'd like.

I would like the hostnames of the static IP devices to be resolvable
within the home network.  That is, if I browse with Windows Explorer
to \LivingRoom or do 'ping LivingRoom' in a command prompt window, it
should resolve the name "LivingRoom" successfully to the IP address.

I do not have a separate DNS server or domain controller set up.  I am
hoping that Sophos Home UTM alone can do this.

The assignment of IP's to devices is working, and if I ping/browse the
IP address for LivingRoom, it works fine.

I am seeing different behaviors for IP-> name resolution depending on
whether the client is a Windows PC or another device (e.g. webcam,
router, Roku)

For a Windows client, if I ping the hostname, it responds, but with
what looks like an IPv6 address response, rather than the IPv4
addresses assigned to it (although pinging the IPv4 address does also
work):


C:\>ping livingroom



Pinging livingroom [fe80::3039:4743:cbe8:b67a%11] with 32 bytes of data:

Reply from fe80::3039:4743:cbe8:b67a%11: time

Using Windows Explorer to browse to \livingroom seems to wrok.

For a non-Windows client, the hostname does not resolve, although the
IPv4 address assigned to the device does respond.


C:\>ping roku

Ping request could not find host roku. Please check the name and try again.



C:\>ping 192.168.1.206



Pinging 192.168.1.206 with 32 bytes of data:

Reply from 192.168.1.206: bytes=32 time=1ms TTL=64

Reply from 192.168.1.206: bytes=32 time

In both Windows and non-Windows cases, I have configured the network
definition of the host along the lines of:


Name: roku

Type: Host

IpV4 Address: 192.168.1.206



DHCP Settings

  IPv4 DHCP: Internal

  Mac Addresses: 



DNS Settings

  Hostname: roku

  Reverse DNS: checked

Please note that although I've used a Roku as an example, the same
behavior is seen with any non-Windows PC client, including an HP
printer, webcams, Chromecast, wireless routers, smartphones, IP
connected appliances like TV's, etc.

Can anyone get me pointed in the right direction?

Thanks,
Arbeleg

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adhodgson · Answer

Hi,

I had the same issues a few weeks back.  The good news is this is possible to fix using these instructions:

Go into the DHCP options for the network and specify your domain in the search domain suffix.  This can be a bogus domain if you wish, for example surname.local etc.

Next renew the DHCP lease.  When you renew, you should see the domain name under the default domain if using for example ipconfig.

Now, when you create a static host entry, under the hostname enter the FQDN i.e, livingroom.surname.local and tick the reverse DNS box.

Note you don't need to tick this box, it won't make any difference to forward name resolution.

You should now be able to run the command ping livingroom and get the response back from the IP address.  Note a Windows client may still use an IPV6 loopback address for this, but if IPV6 is disabled or using a client which doesn't use IPV6 you will get the response back.

Hope this helps.
Andrew.

Getting DHCP-assigned static IP hostnames to resolve in home network

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