> Looking around... so you're talking about scripts in /etc/NetworkManager/dispatcher.d, as documented in NetworkManager(8)?
Yeah. That is how a administrator manually add functionality to NetworkManager. It's very similar in concept to 'init' scripts. Network Manager dispatcher will execute those scripts with a arguments to indicate the state of the interface and which interface it is.
I haven't figured out a good way to manage bridges that way yet. It's on my list of things to do. Right now I just tell Network Manager to leave certain interfaces alone by editing /etc/NetworkManager/NetworkManager.conf. And then using ifcfg or rc scripts.
If I figure out a good way this evening then I'll post it.
I've typically used dispatcher in the past to connect to VPNs that don't have a compatibile plugin for network manager.
> At testing events a few times a year I just turn off NetworkManager and configure stuff manually, but then it's always a pain going back and forth between the test network and the hotel where I want NetworkManager to do its usual thing without thinking about it....
The trick I've found to configuring things "manually" with NetworkManager is to disable the 'native' ifcfg-rhat support for configurations and use keyfile configuration back end. This can be done by editing the NetworkManager.conf file.
The ifcfg support that NM has is subtly different, and I think limited, compared with the the ifcfg support that exists when using the old Redhat-style scripts with NetworkManager turned off. So I hate it. It's difficult to follow documentation and edit ifcfg scripts in a compatible way.
However /etc/NetworkManager/system-connections/ keyfiles provide a ini style configuration method that is fairly easy to wrap your head around if you have examples to go off of. NetworkManager monitors that directory for changes and will automatically implement changes when you exit out of your editor. Copying a config to it will turn on that config, moving it away with disable it. I think that Arch Linux and Gentoo provides decent documentation. If you disable ifcfg and use keyfiles then NM will generate configs that you can later go on and edit.