Ubuntu

1. On the upper-right of the screen, right-click on the Network Icon and select Edit Connections to open the Network Connections Manager.

2. In the Network Connections dialog, select the connection type from the tabs (i.e. Wired).

3. Under the selected tab (Wired in this example), highlight your connection (Auto etho) and click Edit.

4. In the Editing window, select the IPv4 Settings tab.

5. Under IPv4 Settings, change the Method to "Automatic (DHCP) addresses only".

6. Enter the Mailshell nameserver addresses in the DNS Servers field: 209.157.66.245, 74.208.45.33.

7. Click OK and reboot.

8. NOTE

Your settings may reset after reboots or after periods of inactivity. The following command line changes may be needed:

    $ sudo cp /etc/resolv.conf /etc/resolv.conf.auto 
    $ gksudo gedit /etc/dhcp3/dhclient.conf
    # append the following line to the document 
    prepend domain-name-servers 209.157.66.245,74.208.45.33; 
    # save and exit 
    $ sudo ifdown eth0 && sudo ifup eth0 

Additionally, you may need to change eth0 to your network device's name if it uses a non-standard name.