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Routing / ip_forward seems broken

Started by papavector, May 03, 2021, 09:20:35 PM

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Greetings.  I have setup a ppp client (OpenForti-GUI) in a SparkyLinux (SL) VM in order to connect to a VPN.  So far I love everything about SL, but this is my primary use case and forwarding traffic to ppp0 seems to be broken.  I have a similar configuration setup and working in Ubuntu 20.04, but I was looking for a lighter-weight platform to route my local traffic over the VPN.  I am not trying to NAT, just route traffic from eth1 to the ppp0 interface that OpenForti-GUI establishes when connected to my VPN.

I also have a Squid proxy in SL and it is working fine to forward web traffic via web proxy from my Host (macOS) to the ppp network, so I know at least that much works.

Troubleshooting steps (obviously with the SL virtual machine connected to the VPN)

1. DNS resolution and network access for the VPN works from within SL
2. I have IPv6 disabled
3. I have confirmed that net.ipv4.ip_forward = 1.  From everything I can tell if the value 1 "sticks" when set, then ip forwarding is compiled into the kernel, forwarding is enabled in the kernel, and it should be working.  This was the setting I had to change to make the existing Ubuntu work as a router.
4. Firewall is disabled (confirmed iptables -L ; INPUT/OUTPUT/FORWARD all ACCEPT and no defined rules)
5. Traceroute from the Mac to a VPN subnet only shows the first hop to the SL virtual machine's host-only IP, and then stops there
6. Using squid within the SL as a web proxy allows web traffic to flow from macOS browsers to VPN web services

I have reviewed plenty of articles for Ubuntu and Debian and from everything I've read, this should be working.

Are there additional step(s) in SparkyLinux to make it act as a network router?

Thank you

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