Fri May 14, 2021 6:54 pm
What actually works - and is functionally the same - is the following:
A == Remote router with remote IP
B == Local router without IP but with PPPOE server
C == Client dialling PPPOE that needs to communicate out to the internet via remote IP
A: bridge-ppp with eoip-ppp on it, eoip-ppp connects to Router B. bridge-ppp has the gateway IP on it. Say 203.0.113.1/30
B: bridge-ppp with eoip-ppp on it, eoip-ppp connects to Router A. PPP profile for PPPOE - blank - nothing in Bridge or anything. PPPOE server on bridge-lan. PPPOE secret as you like.
C: Client dials PPPOE with secret.
If you have control over router A, simply run the PPPOE server there instead, and instead of bridge-ppp on B, user bridge-lan. If you don't have control of router A, the above is half of the solution - - to make it work like a half bridge you have to do the following:
On PPP Secret, add a randomized Local Address eg. 10.113.0.1 - and the relevant remote address eg. 203.0.113.2
On the Router B bridge-ppp, under ARP, enable Proxy ARP.
On the router B bridge-ppp, add an adjacent IP address - use the broadcast address if you must, in this case: 203.0.113.3 -- this is the key. Yes its a hack, hopefully this address is not needed from here!
On router B - add SNAT and DNAT to and from the random IP (10.113.0.1) to the remote IP (103.0.113.2).
Whala! So, ... DONT DO THIS! KEEP YOUR NETWORK SIMPLE!
But just posted here to show that you can simulate a half bridge setup even without PPPOE-relay.