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psycketom

Member

Registered: 2012-07-29

Posts: 15

[SOLVED] Custom systemd network daemon: how to set DNS?

By default I am running a static-ethernet network profile, that I operate through netctl and which can ping outside too. While working on this configuration, I have disabled the profile from autostarting, so on system boot, I end up with no connection.

What I am trying to achieve here, is a simplified configuration file to be manipulated by a web-based OS configuration panel. Apparently, everything I have attempted has given me no results.

First, I tried what's specified here and there. Those appear to be the same, with the exception of first one being configured from outer resource.

Configuration

/srv/conf.d/stone-roaming:

address=192.168.1.160
netmask=24
broadcast=192.168.1.255
gateway=192.168.1.254

/srv/systemd/system/stone-roaming.service:

[Unit]
Description=STONE Roaming network daemon
Wants=network.target
Before=network.target
BindsTo=sys-subsystem-net-devices-net0.device
After=sys-subsystem-net-devices-net0.device

[Service]
Type=oneshot
RemainAfterExit=true
EnvironmentFile=/etc/conf.d/stone-roaming

ExecStart=/sbin/ip link set dev net0 up
ExecStart=/sbin/ip addr add ${address}/${netmask} broadcast ${broadcast} dev net0
ExecStart=/bin/sh -c 'test -n ${gateway} && /sbin/ip route add default via ${gateway}'

ExecStop=/sbin/ip addr flush dev net0
ExecStop=/sbin/ip link set dev net0 down

[Install]
WantedBy=multi-user.target

Apparently, this only worked to some extent.

Execution routine:

# systemctl start stone-roaming
# systemctl status stone-roaming
stone-roaming.service - STONE Roaming network connection daemon
   Loaded: loaded (/etc/systemd/system/stone-roaming.service; disabled)
   Active: active (exited) since Wed 2013-07-10 12:41:39 FET; 2min 20s ago
  Process: 238 ExecStart=/bin/sh -c test -n ${gateway} && /sbin/ip route add default via ${gateway} (code=exited, status=0/SUCCESS)
  Process: 236 ExecStart=/sbin/ip addr add ${address}/${netmask} broadcast ${broadcast} dev net0 (code=exited, status=0/SUCCESS)
  Process: 234 ExecStart=/sbin/ip link set dev net0 up (code=exited, status=0/SUCCESS)

Jul 10 12:41:39 stone systemd[1]: Started STONE Roaming network connection daemon.

Afterwards, I try to ping in the order of...
gateway:

# ping -c 3 192.168.1.254
PING 192.168.1.254 (192.168.1.254) 56(84) bytes of data.
64 bytes from 192.168.1.254: icmp_seq=1 ttl=64 time=0.299 ms
64 bytes from 192.168.1.254: icmp_seq=2 ttl=64 time=0.314 ms
64 bytes from 192.168.1.254: icmp_seq=3 ttl=64 time=0.287 ms

--- 192.168.1.254 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1998ms
rtt min/avg/max/mdev = 0.287/0.300/0.314/0.011 ms

DNS server:

# ping -c 3 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=49 time=21.0 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=49 time=20.0 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=49 time=19.7 ms

--- 8.8.8.8 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 19.737/20.283/21.091/0.605 ms

ISP provider:

# ping -c 3 92.63.81.4
PING 92.63.81.4 (92.63.81.4) 56(84) bytes of data.
64 bytes from 92.63.81.4: icmp_seq=1 ttl=62 time=5.08 ms
64 bytes from 92.63.81.4: icmp_seq=2 ttl=62 time=3.33 ms
64 bytes from 92.63.81.4: icmp_seq=3 ttl=62 time=4.54 ms

--- 92.63.81.4 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 3.335/4.321/5.080/0.732 ms

other sites:

# ping -c 3 google.com
ping: unknown host google.com

Ah-ha! And this is where the problem relies.

In netctl profiles I can set DNS entries, hence it automatically maps to them, but in my stone-roaming.service I do not specify them, nor I do know how.

How'd I set DNS from my stone-roaming.service?
Or, if my solution or idea is wrong, then what is the way to go here?

Last edited by psycketom (2013-08-06 14:48:48)

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: [SOLVED] Custom systemd network daemon: how to set DNS?

DNS servers are listed as "nameserver ip.add.re.ss" in /etc/resolv.conf.  So I imagine that you would just need something that writes that file for you.

tomk

Forum Fellow

From: Ireland

Registered: 2004-07-21

Posts: 9,839

Re: [SOLVED] Custom systemd network daemon: how to set DNS?

Or you can just hardcode them there, since you're connecting to the same network every time.

psycketom

Member

Registered: 2012-07-29

Posts: 15

Re: [SOLVED] Custom systemd network daemon: how to set DNS?

I ended up with an extra bash script, that I have added to ExecStart and ExecStop respectively to manipulate the DNS servers.

@tomk, while, yes, I am connecting to the same network, the configuration can be changed from the web interface. And not only the ethernet interface values, also the nameservers.