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Enverex

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From: UK

Registered: 2007-06-13

Posts: 159

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[SOLVED] SystemD-NetworkD Keeps Getting New IPs

I've recently switched to using SystemD-NetworkD for network connectivity and I've run into a problem; When a machine comes out of standby/suspend, NetworkD appears to use DHCP to get another IP address (even though the lease on the old one hasn't expired yet) and doesn't drop the old one. Over the space of 2 days, this resulted in one machine having 13(!!) IP addresses concurrently assigned to it.

Is anyone aware of this bug and fix for it?

EDIT: It was the "Critical" option in the systemd-networkd config for this interface. Apparently marking something as critical means it will never drop its (old) leases.

Last edited by Enverex (2015-09-22 15:30:41)

Enverex

Member

From: UK

Registered: 2007-06-13

Posts: 159

Website

Re: [SOLVED] SystemD-NetworkD Keeps Getting New IPs

As an update to this, here's an example of a machine that now has 2 addresses:

● systemd-networkd.service - Network Service
   Loaded: loaded (/usr/lib/systemd/system/systemd-networkd.service; enabled; vendor preset: enabled)
   Active: active (running) since Tue 2015-09-22 08:44:30 BST; 6h ago
     Docs: man:systemd-networkd.service(8)
 Main PID: 275 (systemd-network)
   Status: "Processing requests..."
   CGroup: /system.slice/systemd-networkd.service
           └─275 /usr/lib/systemd/systemd-networkd

Sep 22 08:44:28 ce00 systemd[1]: Starting Network Service...
Sep 22 08:44:30 ce00 systemd-networkd[275]: Enumeration completed
Sep 22 08:44:30 ce00 systemd[1]: Started Network Service.
Sep 22 08:44:33 ce00 systemd-networkd[275]: eth0: Gained carrier
Sep 22 08:44:39 ce00 systemd-networkd[275]: eth0: DHCPv4 address 192.168.204.211/24 via 192.168.204.1
Sep 22 08:44:39 ce00 systemd-networkd[275]: eth0: Configured
Sep 22 13:37:31 ce00 systemd-networkd[275]: eth0: Lost carrier
Sep 22 13:37:31 ce00 systemd-networkd[275]: eth0: DHCPv4 connection considered system critical, ignoring request to reconfigure it.
Sep 22 13:37:34 ce00 systemd-networkd[275]: eth0: Gained carrier
Sep 22 13:37:40 ce00 systemd-networkd[275]: eth0: DHCPv4 address 192.168.204.231/24 via 192.168.204.1

The carrier was likely lost originally due to the machine going onto standby. Looks like when it gets a new IP, it doesn't drop the old lease.

alphaniner

Member

From: Ancapistan

Registered: 2010-07-12

Posts: 2,810

Re: [SOLVED] SystemD-NetworkD Keeps Getting New IPs

Seems like you need to figure out why

DHCPv4 connection considered system critical, ignoring request to reconfigure it.

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Enverex

Member

From: UK

Registered: 2007-06-13

Posts: 159

Website

Re: [SOLVED] SystemD-NetworkD Keeps Getting New IPs

Yeah, I know what's causing that. I guess disabling the Critical option will let it "unlease" addresses then. Well that solves the Arch side of things, now to find out why the DHCP server is issuing new addresses all the time rather than the same one to each machine...