Tag Archives: ds211j

Synology DHCP Server and Firewall

I own a Synology DS211j. As i wanted to use an alternative DHCP mechanism to support custom nameservers i ran into the Synology DHCP Server package, straight-forward and easy to use. Additionally i’ve the Synology  firewall configured to deal with a few ports that are opened to the Internet.

This quick howto gives you tips on how to configure your Synology firewall to work together with the DHCP server package:

Synology DHCP Server and Firewall

Synology DHCP Server and Firewall

I own a Synology DS211j. As i wanted to use an alternative DHCP mechanism to support custom nameservers i ran into the Synology DHCP Server package, straight-forward and easy to use. Additionally i’ve the Synology  firewall configured to deal with a few ports that are opened to the Internet.

I found out that using the DHCP server in combination  with the firewall gave problems; it simply did not function. To let it function in combination with the DHCP server package, open the following ports and allow ALL traffic to it:

1. Source port 67 and 68, UDP;

2. Destination port 67 and 68, UDP.

The above ports are not exactly correct compared with the DHCP standard (RFC 2131), though this was the only way i got it working correctly.

Note that i’m not aware of your already existing firewall rules, make sure these settings don’t bite each other!

To configure this using DSM on your Synology:

1. Login to DSM with administrator privileges;

2. Click on ‘Controlpanel;’

3. Click on ‘Firewall’;

4. Click on ‘Create’,we first create the ‘source’ part of the configuration;

5. Click on ‘Custom’;

Make sure it looks similar like this:

 

 

 

 

 

 

 

 

6. Click on ‘OK’;

7. Click ‘OK’ again;

You now returned to the general part of the firewall configuration, click create again to ‘destination’ part of the configuration.

8. Click ‘Create’;

9. Click ‘Custom’;

Make sure it looks similar like this:

 

 

 

 

 

 

 

 

10. Click on ‘OK’;

11. Click ‘OK’ again;

12. Click ‘Save’ to make the changes permanent.

Have fun!