The open dns addresses: 220.67.222.222, 208.67.220.220

If you want to make the open dns addresses to be more permanent, you may try this option, which requires you to open a terminal:

1. Edit /etc/resolv.conf:
sudo pluma /etc/resolv.conf

2. If any nameserver lines appear, write down the IP addresses for future reference.

3. Replace the nameserver lines with, or add, the following lines:
prepend domain-name-servers 220.67.222.222, 208.67.220.220

4. Save and exit.

5. Restart any Internet clients you are using.

I do not guarantee that the above will work. Problems with connecting with the repositories are varied and so are the solutions.