PPPoE Connection Issue

[Liran]

I've installed OPNsense 26.1.6_2 on a Lenovo M720q with 5 NICS (built-in + 4 i226v PCIe).
I've followed every guide I've found to configure PPPoE, my ISP does not require VLAN tagging so I skipped that.

For some reason when the PPPoE connection is established, the device is getting an 10.x.x.x IP address instead of my public one. According to the ISP, when this IP shows as connected they see a connection.

Previously I was using a Cisco RV-345, when connected again it works. The ISP even provided me a set of testing credentials to see if it's an issue with the credentials.

[franco]

Hi,

I'm not sure without logs and setup you employ, but this topic sounds similar:

https://forum.opnsense.org/index.php?topic=32995.0


Cheers,
Franco

[meyergru]

There are at least three potential reasons for this:

1. Your ISP uses another IP on top of the PPPoE connection (like described in the thread Franco linked to.
2. Your ISP gives you an RFC1918 IP and does CG-NAT on that.
3. Your ISP hands out some RFC1918 IP when the WAN MAC changes and wants you to register the the MAC / router on a private site, before completing that step, you will only have limited access, but no internet.

Ask your ISP which is the case.

Either way, you probably need to uncheck "block RFC1918" on the WAN interface.

[Liran]

There are at least three potential reasons for this:

1. Your ISP uses another IP on top of the PPPoE connection (like described in the thread Franco linked to.
2. Your ISP gives you an RFC1918 IP and does CG-NAT on that.
3. Your ISP hands out some RFC1918 IP when the WAN MAC changes and wants you to register the the MAC / router on a private site, before completing that step, you will only have limited access, but no internet.

Ask your ISP which is the case.

Either way, you probably need to uncheck "block RFC1918" on the WAN interface.

My ISP, like most ISPs, are not very helpful once you connect your own device and their actual technical knowledge is lacking at best.

That being said, I did uncheck the RFC1918 tickbox so it does bot block internal IPs.


I'm pretty sure it's not #3, they don't work like that here. It'd compkicate them more than anything else. I also talked to them and they did not mention registering the MAC (there's a GPON that's their's anyway, so that's what's registered).

Considering my Cisco gets the correct WAN IP, it's not #2.

#1 seems the most reasonable, maybe I'm seeing the next hop in the way out?

What logs would be helpful to try and understand what's the cause?

[chemlud]

Have you tried spoofing the Cisco WAN MAC to your sense WAN?

[Liran]

Have you tried spoofing the Cisco WAN MAC to your sense WAN?

Yes.

I also tried to disconnect the GPON for a couple of hours to male sure the Cisco session is not active anymore and then connecting the OPNsense box.