Arch Linux

mcloaked

Member

From: Yorkshire, UK

Registered: 2012-02-02

Posts: 1,351

question about nsswitch.conf.pacnew changed lines

On the recent update to filesystem (2015.09-1 -> 2016.12-2) there was a warning "warning: /etc/nsswitch.conf installed as /etc/nsswitch.conf.pacnew" - and in my system the old and new config files were:

$ cat /etc/nsswitch.conf
# Begin /etc/nsswitch.conf

passwd: files
group: files
shadow: files

publickey: files

#hosts: files dns myhostname
hosts: files mdns4_minimal dns mdns4 myhostname

networks: files

protocols: files
services: files
ethers: files
rpc: files

netgroup: files

# End /etc/nsswitch.conf

and

$ cat /etc/nsswitch.conf.pacnew 
# Begin /etc/nsswitch.conf

passwd: compat mymachines systemd
group: compat mymachines systemd
shadow: compat

publickey: files

hosts: files mymachines resolve [!UNAVAIL=return] dns myhostname
networks: files

protocols: files
services: files
ethers: files
rpc: files

netgroup: files

# End /etc/nsswitch.conf

The lines for passwd, group and shadow as well as the hosts: line are different in my case but I was not sure whether leaving the existing file in place or to include the new parameters was the appropriate way forward. I had thought that the use of "resolve" for the hosts: line was specific to using systemd-networkd, which I don't use. But should I include "resolve" as well even though I don't use systemd-networkd?  I also presume that "mymachines" was a token meaning to add in specific machine names for the LAN? I could not find a clear description of this when I searched.

For the passwd, group and shadow lines my understanding was that replacing "files" by "compat" would be fine since this seems to include the behaviour of "files" but with additional control over inclusion and exclusion of specific users? Is it now important to include "systemd" in those lines, and does it matter if I don't? Or is that parameter only needed if you are using systemd-resolved? Does anyone have a link to a clear description of whether leaving one's existing nsswitch.conf file in place would not be a good way forward?

Hopefully this can be easily clarified - or maybe I just missed a thread on this being discussed elsewhere?

Last edited by mcloaked (2016-12-10 15:20:54)

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Mike C

jjacky

Member

Registered: 2011-11-09

Posts: 347

Website

Re: question about nsswitch.conf.pacnew changed lines

"resolve" refers to systemd-resolved yes, "mymachines" & "myhostname" are also systemd-related actions. I won't comment as to what you should or shouldn't do - though obviously the "official" way under Arch would be to have them enabled - but you can read about what those do in their respective man pages: nss-systemd(8), nss-myhostname(8), nss-mymachines(8) & nss-resolve(8)

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blog - github

teateawhy

Member

From: GER

Registered: 2012-03-05

Posts: 1,138

Website

Re: question about nsswitch.conf.pacnew changed lines

Also related to this update, can someone clarify if this part of the wiki needs to be changed? I have marked it as out of date for now.
https://wiki.archlinux.org/index.php/Av … resolution

9c9
< hosts: files mhdns_minimal [NOTFOUND=return] dns myhostname
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> hosts: files mymachines resolve [!UNAVAIL=return] dns myhostname

EDIT: Wiki was updated.

Last edited by teateawhy (2016-12-11 11:12:09)