If you are connecting to a Unifi L2TP Server type Remote User VPN and you haven’t selected the “Send all traffic over VPN connection” option under advanced settings on the Mac.
![](https://toggen.com.au/wp-content/uploads/2022/01/Screen-Shot-2022-01-18-at-7.24.24-pm.png)
You will need to set routes so you can access a LAN or LANs behind your UDM
If you are wondering what is being passed to the the /etc/ppp/ip-up echo the arguments to /tmp/ip-up by uncommenting the “# echo \"$0\" \"$1\" \"$2\" \"$3\" \"$4\" \"$5\" \"$6\" >> /tmp/ip-up
” line
I want to set routes based on the IP of the remote VPN-Server so argument $5 is the one that I have put into the case block to add routes.
I found I didn’t need an /etc/ppp/ip-down
script because the routes added by /etc/ppp/ip-up
go away when the ppp0
connection created by the L2TP / IPSec tunnel goes away
Create an ip-up script to set routes when L2TP/IPSec connection comes up on MacOS
This script was on the Unifi forums but posting here so I can find it easier than I did last time.
#!/bin/bash
# /etc/ppp/ip-up
# uncomment this and start the connection to your UDM/USG to check what is being passed to this script
# escaping the quotes are needed because one of the arguments is there but empty
# echo \"$0\" \"$1\" \"$2\" \"$3\" \"$4\" \"$5\" \"$6\" >> /tmp/ip-up
# $0. $1 $2 $3 $4 $5 $6
# this-script interface-name tty-device speed local-IP-address remote-IP-address local-gateway
# "/etc/ppp/ip-up" "ppp0" "" "0" "192.168.73.1" "10.255.255.0" "192.168.1.1"
case "$5" in
# Based on vpn-server-ip, do different things
10.255.255.0)
/sbin/route add 10.197.4.0/24 10.255.255.0
/sbin/route add 10.11.12.0/24 10.255.255.0
# anything else could also go here
;;
some.other.ip.address)
# some.other.ip.address could be another VPN server and you can
# do different stuff here.
;;
yet.another.ip.address)
;;
*)
;;
esac
exit 0
If you are more comfortable with GNU/Linux utilities for listing IP addresses then install
brew install iproute2mac
# you can then list routes easier with
ip route
# output
default via 192.168.1.1 dev en0
default via link#17 dev ppp0
10.197.4.0/24 via 10.255.255.0 dev ppp0
10.255.255.0/32 via 192.168.73.1 dev ppp0
110.174.183.220/32 via 192.168.1.1 dev en0
127.0.0.0/8 via 127.0.0.1 dev lo0
127.0.0.1/32 via 127.0.0.1 dev lo0
169.254.0.0/16 dev en0 scope link
192.168.1.0/24 dev en0 scope link
192.168.1.1/32 dev en0 scope link
192.168.1.104/32 dev en0 scope link
192.168.73.0/24 via ppp0 dev ppp0
224.0.0.0/4 dev en0 scope link
224.0.0.0/4 dev ppp0 scope link
255.255.255.255/32 dev en0 scope link
255.255.255.255/32 dev ppp0 scope link
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