As shown in the diagram below, I currently have three systems networked together:
Interface eno2
IP Addresses Assigned:
192.10.10.12───────────┐
│
│
│
│ ┌─────────────────────────┐
┌─────────────────────────┐ │ │ │
│ │ │ │ │
│ │ │ │ Computer C │
│ Computer A ├─┤ ETH INTERFACE ┌─┤ │
│ │ │◄───────────────────►│ │ │
│ ├─┘ ├─┤ │
│ │ │ │ │
│ │ │ └─────────────────────────┘
Interface enp134s0f1 └───────────┬──┬──────────┘ │
IP Addresses Assigned ├─▲┘ │
192.168.200.12 │ │ │
192.168.200.11 │ │ │
│ │ │ Interface eno1
───────────────────┘ │ └───────────────── IP Addresses Assigned:
│ 192.10.10.13
│ 192.168.200.13
│ 5.5.5.1
│
│ETH
Interface enp134s0f1 │INTERFACE
IP Addresses Assigned │
192.168.200.10 │
5.5.5.3 ────────────────────────┐ │
├─▼─┐
┌──────────┴───┴──────────┐
│ │
│ │
│ Computer B │
│ │
│ │
│ │
│ │
└─────────────────────────┘
The objective is to have bidirectional communication between Computer C and Computer B via simple pings and ssh sessions.
For Computer B, I've added the following addresses and routes to the system:
ip route add 192.168.200.0/24 via 192.168.200.12
ip route add 5.5.5.1/32 via 192.168.200.12
Interface enp134s0f1 IP Address assigned:
For Computer A, the following addresses and routes were added along with modifications to the NAT table:
ip route add 192.168.200.13/32 via 192.10.10.12
ip route add 5.5.5.1/32 via 192.10.10.12
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -o eno2 -j SNAT --to-source 192.10.10.12
Interface eno2 IP Address assigned:
Interface enp134s0f1 IP Address assigned:
- 192.168.200.11
- 192.168.200.12
For Computer C, I've added the following addresses and routes to the system:
ip addr add 5.5.5.1/24 dev eno1
ip addr add 192.168.200.13/24 dev eno1
ip route add 192.168.200.0/24 via 192.10.10.13 dev eno1
ip route add 5.5.5.0/24 via 192.10.10.13 dev eno1
Interface eno1 IP Address assigned:
- 192.10.10.13
- 192.168.200.13
- 5.5.5.1
I can currently communicate in the following direction from Computer B to Computer C with this network configuration:
+------------+ PING or SSH +------------+ PING or SSH +------------+
| Computer B | ------------> | Computer A | ------------> | Computer C | ✓
+------------+ +------------+ +------------+
However, I'm having no luck with ping or ssh sessions in the opposite direction.
+------------+ PING or SSH +------------+ PING or SSH +------------+
| Computer B | <------------ | Computer A | <------------ | Computer C | X
+------------+ +------------+ +------------+
Each computer are running different flavors of Linux as well:
- Computer A : Ubuntu 16.04 LTS
- Computer B: CentOS7
- Computer C: Ubuntu 20.04 LTS
I am not sure if my modifications to the NAT rules are set up correctly or not.
