I've been having this issue for a long time with 10.13.4 beta which ObDev didn't want to address. Its now a fully released MacOS 10.13.4 updated with the combo installer.
Before LS installation, everything is working fine, can access the Internet, ping, etc. Install LS 4.0.6, reboot .within minutes my network is hung and so is every process using the network ..like Drobbox, Firefox, Safari, even ping to my local network in the terminal. Using the LS uninstall, that too is hung.
So I use LingonX to disable 2 of the 3 obdev processes (littlesnitchd would not disable and hung LingonX).
Reboot, run the LS uninstaller again, reboot and everything is back to the way it is. Y'all have known about this problem for at least a month. Lets get a fix now. There is no excuses!