Description:

When using `netctl stop ${profile}', if the profile uses dhcpcd to configure DNS information through resolvconf, then the resolvconf entries are not cleared. Usually dhcpcd figures this out when the same interface is restarted with a new profile. However, it can cause issues when a new profile is started on a *different* interface, and the DNS information from the first interface is no longer valid. I put an example use-case at the bottom, in the "Steps to reproduce" section.


Additional info:

* package version(s)
I updated everything a couple days ago. In particular my netctl copy is up to date with the official repositories.

* config and/or log files etc.
See attached file, "dhcpcd-session.txt" for an example of how stopping dhcpcd in different ways can lead to different behaviors with resolvconf.


Steps to reproduce:

Suppose your laptop has two interfaces, wlan0 and eth0.

At home, you use a local DNS server at 192.168.1.1, which is the default DNS server for anyone connecting and using DHCP. You use the eth0 interface while at home, with DHCP, so this is the default DNS server.

Later, you disable the eth0 interface, suspend/hibernate your laptop, and go to work/school. You connect to the local wifi using wlan0. This gives you new DNS addresses, say Google's 8.8.8.8. However, when you try to connect to the Internet, DNS resolution becomes very slow.

The reason is that the old eth0 information is still present, and has been given a higher priority (for whatever reason), so your machine always tries to check with 192.168.1.1 for DNS resolution, waiting for a timeout, and then continuing with 8.8.8.8.


Work-arounds:

This can be fixed by running `resolvconf -d ${interface}' to remove the old DNS information. I doubt this runs the other dhcpcd hooks though, which might be causing other problems on the system.