Braincoke

A collection of notes taken when tinkering with technology. I also have another website (link below) to record personal solutions to security challenges.

Solving QNAP NAS network issues

3 minute read

What to do when you have network issues on your QNAP NAS ?

Evaluating the damage

First off, it might be nice to connect the NAS to a screen and a USB keyboard. With ALT+F2 you can use a terminal and connect with an administrator account. If there is no terminal, well this is really bad, and this is not the correct documentation for this problem.

If there is a terminal, you can investigate.

Ping

From the NAS :

  • Can you ping your router ?
  • Can you ping another machine on the same network ?
  • Can you ping another machine on the same network but a different medium (Wi-Fi instead of Ethernet) ?
  • Can you do part of, or all of the above, but with host names instead of IP addresses ?
  • Can you ping a machine on the internet (try a popular DNS IP address) with its IP ?
  • Can you do the same with its host name ?

From another machine :

  • Can your router ping the NAS ?
  • Can a machine from your network ping the NAS ? On a different medium too ?

If the NAS can ping the router, then the network card is still working, the problem might come from a firewall or a bad network configuration.

Performing a basic reset

If it appears that the problem comes from a bad network configuration, performing a basic reset will solve the problem.

Procedure

To do so, press the reset button for approximately 3 seconds. You should hear one long beep. Let the NAS do its thing, then try to connect to it.

Warning: If you press the button for 10 seconds, you will hear two beeps and the factory reset will start, which will lead to the complete loss of your data

Consequences

After pressing the reset button for 3 seconds, a beep sound will be heard. The following settings will be reset to default:

  • System administration password: admin.
  • TCP/IP configuration: Obtain IP address settings automatically via DHCP.
  • TCP/IP configuration: Disable Jumbo Frame.
  • TCP/IP configuration: If port trunking is enabled (dual LAN models only), the port trunking mode will be reset to “Active Backup (Failover)”.
  • System port: 8080 (system service port).
  • Security level: Low (Allow all connections).
  • LCD panel password: (blank)1.
  • VLAN will be disabled.
  • Service binding: All NAS services run on all available network interfaces.

Where to go from there

If this does not work, you can perform a hard reset that will ERASE all your data. Or you can investigate further as the problem might still come from a bad network configuration that you might solve. See below for leads to where the problem might lie.

Ping and ARP

If the NAS can ping the router but the router cannot ping the NAS, it might be that your configuration forbids ARP or Ping responses.

Check if ARP is ignored

You can easily check your configuration with this command line:

  find /proc/sys/net/ipv4/conf/br0/arp_* -exec tail -n +1 {} +

The output should be something like this

==> /proc/sys/net/ipv4/conf/br0/arp_accept <==
0

==> /proc/sys/net/ipv4/conf/br0/arp_announce <==
0

==> /proc/sys/net/ipv4/conf/br0/arp_filter <==
0

==> /proc/sys/net/ipv4/conf/br0/arp_ignore <==
0

==> /proc/sys/net/ipv4/conf/br0/arp_notify <==
0

If some of the files do not contain the default value (0), then you can try setting it to 0 and see if it solves your problem.

You can find the IP-Sysctl values for ARP here </div>

Check if ICMP is ignored

You can see if ICMP requests are ignored with this command line.

  find /proc/sys/net/ipv4/icmp_echo_* -exec tail -n +1 {} +

The output should be something like this:

==> /proc/sys/net/ipv4/icmp_echo_ignore_all <==
0

==> /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts <==
1

You can find IP-Sysctl values for ICMP here

Routes

Another problem might be that the routes are not properly configured. Use the following command to show the configured routed:

  $ netstat -nr
Output
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         10.0.0.1        0.0.0.0         UG        0 0          0 eth1
10.0.0.0        0.0.0.0         255.255.240.0   U         0 0          0 eth1
127.0.0.0       0.0.0.0         255.0.0.0       U         0 0          0 lo

The default gateway if the line starting with 0.0.0.0. If you do not have a default gateway, then there is a problem. And you have to manually add it.

Here is the command line to add a default gateway:

  ip route add default via 10.0.0.1

You can also use route and ip route to show the routes

  1. This feature is only provided by the NAS models with LCD panels. Please visit http://www.qnap.com for details. ↩

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