I Currently use a Cisco ASA as Internet facing firewall and it NAT’s my internal address, I would like to put a Mikrotik between the Internet and this and route my public IP’s back to the outside interface of the Cisco from the Mikrotik.
Example IP Range - 11.22.33.144/29
The Mikrotik will obtain 11.22.33.150/29 via PPPoE, whats is the best way to route/assign the remaining address to the WAN of the Cisco.
Kind Regards
Just put the address 11.22.33.150/29 on an ethernet interface…
I guess my question is will i need to use up one of the other address in the inside of the Mikrotik
ISP <—> (11.22.33.150)Mikrotik(11.22.33.149) <—> (11.22.33.148)ASA(10.10.10.1/24)
Nope. PPP is like a wormhole. The IP addresses of each end need not be in the same subnet - PPP doesn’t even need any IP addresses at all to work. All you need is routes that point across the interface by name, and it can do its job just fine.
So when a provider puts x.x.x.x/29 onto your PPPoE session, what really happens is that their router will dump any of those 8 IPs onto the PPP link, and “the other guy will handle it” There’s no ARP or MAC address or anything like that because PPP is a point-to-point (as the name explicitly states) link, which means there are only two parties on it - you and the other guy, so if you send a packet, it must be from you and it must be for the other guy.
If you never put the IP addresses onto any interfaces, you could even use all 8 of the IP addresses (assuming that the zero and broadcast addresses didn’t coincide with a classful network boundary - i.e. 10.1.2.0/29 does not match the classful IP network number 10.0.0.0, so you could use it as a NAT address, whereas 192.168.2.0/29 DOES overlap because 192.168.2.0 is also the class-C network address of 192.168.2.0/24)
So, in short, follow Pe1chl’s advice and it will work perfectly.
Solved my problem! Thanks!