[Openswan Users] Android prevents MacOS clients from connecting from the same external IP

[Jonathan Farnsworth]

I have an openswan with xl2tp setup using NETKEY which works fine most 
of the time. I have had MacOS, Windows and Android clients all 
connecting over 3G (so different external IPs) however, I have noticed 
that when you connect an Android client and then try to connect a MacOS 
client through the same WiFi (so same external IP) the MacOS client 
fails to connect. Looking through the logs the IPsec connection is 
established and running 'ip xfrm state' shows that I have 4 routes (1 
inbound and 1 outbound for both the android and the iphone). I did a 
tcpdump and found that the traffic for the iPhone was actually using the 
Android outbound route. This is only an issue for MacOS clients 
connecting after an Android client connects from the same external IP. I 
can connect a Windows client after an Android and I can connect another 
Android client.
Regards
Jonathan