Asymmetric routing issue with Cloud Advertisement

Hi,

We are trying to build a configuration with 2 Pritunl servers on OCI, accessing on-premises servers through an OCI IPSEC gateway

We need to manage multiple population types and access rules, so we will use multiple VPN ranges ; NAT is disabled on the on-premises range.

VXLAN is enabled on both servers to allow them to share the VPN range, and it works : clients connected on 2 different servers can see each other

OCI route advertisement is configured and works too, however it also publishes the VXLAN range 100.97.162.0/24 ; I’m not sure if this is useful/normal ?

Now the issue : when connected on the server NOT advertised, we can’t open an SSH session to our on-premises server ; however it works OK on the advertised server

I believe it’s an issue of asymmetric routing : on the non-advertised server, packets go out directly through the gateway, but they come back through the advertised server and the VXLAN, causing the issue

To solve it, I added a rule on the non-advertised server to forward all the packets, sent to the on-premises server and originating from the VPN range, to the advertised server through the VXLAN interface
In that way, sent and received packets follow the same routes

Here is what I used (on-premises 192.168.3.0/24, VPN range 171.7.100.0/24)
sudo ip route add table 162 192.168.3.0/24 via 100.97.162.1

sudo ip rule add table 162 from 172.17.100.0/24

And it works!

Could you please add an option somewhere to automate this in the route advertisement module ?

Thanks

The code for this has been added to the repository and will be included in the next release. It will have support for both IPv4 and IPv6. All non-NAT routes will be routed to the server selected for the advertised routes with a routing table for each server. When a failover occurs all tables will be updated to the next selected host.

hi, we are using 1.32.4469.94 and this doesn’t seem to be implemented, no routes are added and if the client connects to the server that doesn’t have the return advertised route, pings don’t work(as expected)

Is there some setting to activate ?

This was added in the server release v1.32.4465.96

ah yes sorry seeing the routes, forgot the use show table 100