When in the office, I'm connected to a 192.168.1.0/24 network. When Internet Sharing is off, when I run

netstat -nr 

the first entry shows

default            192.168.1.254      UGSc           10       62     en0

If I turn Internet sharing on, it shows

default            link#5             UCS             2        0     en1

This is obviously incorrect and breaks all connectivity of my machine.

en1 is my wireless, whereas en0 is my ethernet. If I then disable Internet Sharing, it even deletes that incorrect route, so I'm left with no default route at all.

Currently I have one script that I run when I share, or after, when I disable that does

route delete default
route add default 192.168.1.254

That fixes everything, but I'd love to know what's actually making this happen and how to properly fix it.

And just to say that at some point a few months ago, this was working absolutely perfectly, with no hitches, then one day when I brought the laptop home, I couldn't disable the internet sharing, so I couldn't connect to my home wifi. I eventually had to restart the machine and since then this problem has been happening.

Any help would be greatly appreciated, thank you.