I have a Ubuntu Server I'm using as an Internet router. The interfaces are as follows:

*Internal corporate network*
  dhcp4:  enabled

*Public Direct Fiber Network*
eno2:     50.***.**5.1
  dhcp4:  enabled

*Link to CIENNA*
enp10s0:  50.**.**4.214
  gateway: 50.***.**4.213

Here are my ip routes:

default via 50.***.**4.213 dev enp10s0 proto static dev eno1 proto kernel scope link src dev tun0 proto kernel scope link src
50.**.**4.212/30 dev enp10s0 proto kernel scope link src 50.***.**4.214
50.***.**5.0/24 dev eno2 proto kernel scope link src 50.***.**5.1

Here are my IPTABLES rules for forwarding:

-N f2b-sshd
-N voip-allow
-A INPUT -p tcp -m multiport --dports 22 -j f2b-sshd
-A FORWARD -s -p tcp -m tcp --sport 80 -j ACCEPT
-A FORWARD -s -p tcp -m tcp --sport 443 -j ACCEPT
-A FORWARD -s -p udp -m udp --sport 5060 -j ACCEPT
-A FORWARD -s -p udp -m udp --sport 5061 -j ACCEPT
-A FORWARD -s -p udp -m udp --sport 10000:20000 -j ACCEPT
-A FORWARD -i eno1 -j ACCEPT
-A f2b-sshd -j RETURN

What works: Traffic is forwarded from eno2 to enp10s0 successfully both ways, and my entire block of public IPs work. What doesn't work: Traffic is not forwarded from eno1 to enp10s0 at all on the internal corporate network. I've done trial and error, like:

ip route add dev eno1 via 50.***.**5.1 && many other variations

I also remembered to use

ip route del /*route info*/

in between tests. I've Googled it and messed up my working public IP network more times than I care to county. And so, I throw myself at your mercy. What am I doing wrong here?

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