Monday, January 4, 2010

How to set the Firefox proxy settings

If you want to use Firefox behind a proxy and need to tell it to bypass a range of addresses, this is how you do it:
Press Alt-O, Network, Settings

In 'no proxy for', use the following values. will allow 10.*.*.* will allow 10.0.*.* will allow 10.0.0.*

In summary, the number after the '/' indicates how many bits to 'keep or mask', while allowing any value in the remaining bits of the address, starting from the left.

For example, will cover the range -
(i.e. keep the left 16 bits = 2 octets = '1.2')

For more examples of how this works, visit this CIDR calculator

ps: Comments and/or links to this article are most welcome!