Question

How to set default route for the VPN

I have been able to set up a site-to-site IPSec/IKEV1 VPN between a CISCO gear and my droplet at DO. The VPN is up. But there is not traffic. When I do a simple ping on the remote Private IP from my droplet, I get nothing:

ping 192.168.100.213
PING 192.168.100.213 (192.168.100.213) 56(84) bytes of data.
^C
--- 192.168.100.213 ping statistics ---
21 packets transmitted, 0 received, 100% packet loss, time 20159ms

But if I try to ping the remote Private IP by specifying the interface to use as *eth1, I can reach it smoothly :

ping 192.168.100.213 -I eth1
PING 192.168.100.213 (192.168.100.213) from 10.XXX.XXX.XXX eth1: 56(84) bytes of data.
64 bytes from 192.168.100.213: icmp_seq=1 ttl=63 time=169 ms
64 bytes from 192.168.100.213: icmp_seq=2 ttl=63 time=168 ms
^C
--- 192.168.100.213 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 168.838/169.150/169.462/0.312 ms

How can I solve that ? It feels like when I’m trying to reach out, the default interface is eth0. Is there a way to change the default interface ? or is there a configuration that can help me tell that all the packets that are coming from my private IP of the droplet must pass trough eth1 ?


Submit an answer


This textbox defaults to using Markdown to format your answer.

You can type !ref in this text area to quickly search our full set of tutorials, documentation & marketplace offerings and insert the link!

Sign In or Sign Up to Answer

These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.

jarland
DigitalOcean Employee
DigitalOcean Employee badge
April 10, 2019
Accepted Answer

Greetings!

This is a great question. I really like nixCraft’s guide for adding routes, and I think it can help you in your situation:

https://www.cyberciti.biz/faq/linux-route-add/

I think the most noteworthy part of their guide is where they give the example for “Route all traffic via 192.168.1.254 gateway connected via eth0 network interface.” I would paste it here but they deserve the ad revenue from a visit :)

Jarland

Thanks very much. That answer helped me pinpoint correctly where was my mistakes implementing that VPN. I ended up implementing the routing with iptables : ```iptables -t nat -A POSTROUTING -j SNAT -o eth0 --destination 192.168.XXX.XXX --to-source 10.MYP.RIV.ATE

Try DigitalOcean for free

Click below to sign up and get $200 of credit to try our products over 60 days!

Sign up

Get our biweekly newsletter

Sign up for Infrastructure as a Newsletter.

Hollie's Hub for Good

Working on improving health and education, reducing inequality, and spurring economic growth? We'd like to help.

Become a contributor

Get paid to write technical tutorials and select a tech-focused charity to receive a matching donation.

Welcome to the developer cloud

DigitalOcean makes it simple to launch in the cloud and scale up as you grow — whether you're running one virtual machine or ten thousand.

Learn more
DigitalOcean Cloud Control Panel