SSH from VLAN A to VLAN B - terminal freezes?

Networking & Firewalls
1

I have two VLANs, one being my LAN (VLAN-76) and a new Management LAN (VLAN-100). My servers (Proxmox) are have NICs in both VLANs (76+100) and my clients are only in the main LAN (76).

When I ssh into one of the Proxmox servers via VLAN-100, the connection is created but the shell freezes at some point, it completely stops responding. When I connected by the “common VLAN-76” IP address the connection is remains stable.

I have a pfSense router managing it all but I don’t think that it is causing the problem.

The GW (default) on the servers is currently 192.168.76.254 (proxmox on VLAN 76), is the return traffic not being routed correctly?

The routing looks correct and I thought that incoming connections on a server always go back to the incoming host.

I’m at a bit of a loss here, maybe I can’t see the woods for the trees. Any thoughts are appreciated.

2

You can use pftop to see watch and see if the connections are getting dropped:

1 Like
3

Thanks Tom, I’ll watch your video and give pftop a try.

4

The state shows up as “SYN_SENT:CLOSED”

image
image1152×180 49.8 KB

The connection shows up for a while in pftop also, then disappears after about 30 seconds.

The server has an IP on the client’s network, could it be packets are going to 192.168.100.220 but coming back from 192.168.76.220 ?

To get this to switch over, do I have to move my default gateway from 192.168.76.254 to 192.168.100.254?

5

I switched the gateway from 76 to 100 and it works now. Watching your video helped, thanks @LTS_Tom

1 Like