Dealing with public IP address shortage in Mikrotik

RouterOS Beginner Basics
1

Hi all!

Does anybody know how you can spare some public IP adresses using let’s say PPPoE protocol and NAT? On Cisco you have PAT (port address translation) using the keyword “overload”. I was wondering is similar option possible on Mikrotik?

Thanks very much!

2

http://wiki.mikrotik.com/wiki/Firewall_nat

The masquerade and src-nat actions can be used for PAT.

3

Thank you. But I was wondering can you masquerade one private pool of IP addresses used for PPPoE over smaller one public? You can’t use “masquerade” in this case, can you?
Masquerade “translates” some private addresses over one public (outgoing) address put on the public interface. In Cisco (sorry for reffering to Cisco again :slight_smile: ) overload keyword can be used in the situation like this - translate, let say pool of 30(/27) addresses over one public of 14(/28) addresses. Is this possible in Mikrotik and how.
Thank you very much! And thanks for your answer!

4

You can’t use masquerade in that situation, but you can use src-nat. With the src-nat action you get the to-addresses parameter, which lets you define a range:

to-addresses (IP address[-IP address]; Default: 0.0.0.0) - Replace original address with specified one. Applicable if action is dst-nat, netmap, same, src-nat

If you have discontinuous ranges you can use random or nth to spread (relatively) evenly over multiple pools.

5

Thank you very much!
I knew I shouldn’t use masquerade, but wasn’t really sure if I could achieve that what I mentioned. You answered my question.
Thank you once again! :smiley: