Comment 5 for bug 1886809

This is a ubuntu desktop. A corporate laptop.

> cat /etc/network/interfaces
# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback

> cat /etc/network/interfaces.d/*
fish: No matches for wildcard “/etc/network/interfaces.d/*”. See `help expand`.
cat /etc/network/interfaces.d/*
    ^

> cat /etc/netplan/*
# Let NetworkManager manage all devices on this system
network:
  version: 2
  renderer: NetworkManager

As you can see this is network-manager based settings.

Pulsesecure is a sort of java browser based application. Since it is a proprietary application, I'm not sure how it runs internally, but it does some basic checkings into your system to allow the connection, and establishes it. It changes all routes to use the VPN as default. Any attempt to change is detect and it considers an attempt to tamper with system, which results in connection drop. That's where the avahi causes the problem.

One extra info: I set the avahi to disable on /etc/default/avahi-daemon.

> cat /etc/default/avahi-daemon
# 1 = Try to detect unicast dns servers that serve .local and disable avahi in
# that case, 0 = Don't try to detect .local unicast dns servers, can cause
# troubles on misconfigured networks
AVAHI_DAEMON_DETECT_LOCAL=0

So even a patch o top of avahi-autoipd that reads this parameter can be enough to avoid this unwanted route to pop up.