# Linux strongSwan IPsec Clients (e.g., OpenWRT, Ubuntu Server, etc.)
Install strongSwan, then copy the included ipsec_user.conf, ipsec_user.secrets, user.crt (user certificate), and user.key (private key) files to your client device. These will require customization based on your exact use case. These files were originally generated with a point-to-point OpenWRT-based VPN in mind.
4.`/etc/ipsec.d/cacerts`: copy `cacert.pem` from `algo-master/configs/<server_ip>/ipsec/manual/cacert.pem`
5.`/etc/ipsec.secrets`: add your `user.key` to the list, e.g. `<server_ip> : ECDSA <name>.key`
6.`/etc/ipsec.conf`: add the connection from `ipsec_user.conf` and ensure `leftcert` matches the `<name>.crt` filename
7.`sudo ipsec restart`: pick up config changes
8.`sudo ipsec up <conn-name>`: start the ipsec tunnel
9.`sudo ipsec down <conn-name>`: shutdown the ipsec tunnel
One common use case is to let your server access your local LAN without going through the VPN. Set up a passthrough connection by adding the following to `/etc/ipsec.conf`:
conn lan-passthrough
leftsubnet=192.168.1.1/24 # Replace with your LAN subnet
rightsubnet=192.168.1.1/24 # Replace with your LAN subnet
authby=never # No authentication necessary
type=pass # passthrough
auto=route # no need to ipsec up lan-passthrough
To configure the connection to come up at boot time replace `auto=add` with `auto=start`.
## Notes on SELinux
If you use a system with SELinux enabled you might need to set appropriate file contexts:
````
semanage fcontext -a -t ipsec_key_file_t "$(pwd)(/.*)?"
restorecon -R -v $(pwd)
````
See [this comment](https://github.com/trailofbits/algo/issues/263#issuecomment-328053950).
