OpenVPN Support Forum

Posted: **Thu Apr 12, 2018 7:26 pm**

At least, I *think* its a routing problem, but its a bit strange.

This is the setup:

Firewall has port forwarding (1194) set up to the OpenVPN server (Centos 7.2).
The router has a static route 10.8.0.0/24 -> 10.0.0.4 to route vpn traffic rather than having to install routes on every device.

I can connect ok, and can ping any device on the internal or admin networks.
I can ssh to 10.0.0.4 ok.

However, any other TCP connection (webserver, ssh etc.) to anything other than 10.0.0.4 fails.

If I ssh to 10.0.0.4, then to 10.0.0.21, I can ssh to my client (10.8.0.4) - so routing to the VPN gateway seems to be working ok.
(traceroute shows the path going through the MikroTik firewall/gateway as expected)

Routing on 10.0.0.21 is basic:

Code: Select all

$ netstat -r
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
default         10.0.0.1        0.0.0.0         UG        0 0          0 wlan0
10.0.0.0        *               255.255.255.0   U         0 0          0 wlan0

ICMP seems to make the round trip ok (ping), but not TCP????
Suggestions???

Posted: **Thu Apr 12, 2018 8:08 pm**

Ok ... I think I found it.
I was connected to the Internal Network with my Mac to set things up.
Then I switched from the wifi AP on that network to the hotspot on my phone to test.

Looks like caching (probably arp cache?) was the problem. Leave it alone and come back to it later and things start to work.

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