[SOLVED] Help, it seems IPv4 is turned off on my server.

sgtnasty · 2025-03-09 14:35:11

I am running Arch on my mini server. This morning, I tried to ssh into it and could not get a response.
I tried ssh in via my Windows desktop and noticed that it was able to connect using IPv6.
I ran

ip -4 a

and did not see my eno1 interface. But it does show up with

ip -6 a

.
How can I turn on IPv4 again?

Last edited by sgtnasty (2025-03-10 19:10:49)

sgtnasty · 2025-03-09 14:45:46

I have rebooted several times and still IPv4 is turned off.

sgtnasty · 2025-03-09 15:53:30

NetworkManager says IPv4 configuration is "AUTOMATIC", so I rebooted my router and still no IPv4 for the server.

seth · 2025-03-09 16:33:37

Please don't bump, edit your previous post to mend it if nobody has yet replied.
Then please don't paraphrase, https://bbs.archlinux.org/viewtopic.php?id=57855
For a general oversight

ip a
find /etc/systemd -type l -exec test -f {} \; -print | awk -F'/' '{ printf ("%-40s | %s\n", $(NF-0), $(NF-1)) }' | sort -f

Chances are you don't have a lease at all and use the LL/ULA IPv6

sgtnasty · 2025-03-09 18:08:04

Here is the output of the 2 commands you suggested:

$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host noprefixroute
       valid_lft forever preferred_lft forever
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 1c:83:41:29:f7:69 brd ff:ff:ff:ff:ff:ff
    altname enp2s0
    altname enx1c834129f769
    inet6 2600:4040:e11d:2500:5267:31b7:36a:c3f/64 scope global dynamic noprefixroute
       valid_lft 7038sec preferred_lft 7038sec
    inet6 fe80::76b2:4a2:451b:b884/64 scope link noprefixroute
       valid_lft forever preferred_lft forever
3: wlp3s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 9e:6e:b6:0b:e8:72 brd ff:ff:ff:ff:ff:ff permaddr 10:6f:d9:28:aa:c3
    altname wlx106fd928aac3
4: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
    link/ether d6:2b:2d:3a:6f:56 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever
$
$ find /etc/systemd -type l -exec test -f {} \; -print | awk -F'/' '{ printf ("%-40s | %s\n", $(NF-0), $(NF-1)) }' | sort -f
cockpit.socket                           | sockets.target.wants
dbus-org.fedoraproject.FirewallD1.service | system
dbus-org.freedesktop.nm-dispatcher.service | system
dbus-org.freedesktop.timesync1.service   | system
docker.service                           | multi-user.target.wants
fail2ban.service                         | multi-user.target.wants
firewalld.service                        | multi-user.target.wants
getty@tty1.service                       | getty.target.wants
NetworkManager.service                   | multi-user.target.wants
NetworkManager-wait-online.service       | network-online.target.wants
nginx.service                            | multi-user.target.wants
p11-kit-server.socket                    | sockets.target.wants
pmlogger.service                         | multi-user.target.wants
remote-fs.target                         | multi-user.target.wants
sshd.service                             | multi-user.target.wants
syncthing@ronaldo.service                | multi-user.target.wants
systemd-timesyncd.service                | sysinit.target.wants
systemd-userdbd.socket                   | sockets.target.wants
$

Also checked journalctl:

$ journalctl -b | grep eno1
Mar 09 11:56:29 titan kernel: igc 0000:02:00.0 eno1: renamed from eth0
Mar 09 11:56:31 titan NetworkManager[651]: <info>  [1741535791.5823] manager: (eno1): new Ethernet device (/org/freedesktop/NetworkManager/Devices/2)
Mar 09 11:56:31 titan NetworkManager[651]: <info>  [1741535791.5828] settings: (eno1): created default wired connection 'Wired connection 1'
Mar 09 11:56:31 titan NetworkManager[651]: <info>  [1741535791.5828] device (eno1): state change: unmanaged -> unavailable (reason 'managed', managed-type: 'external')
Mar 09 11:56:37 titan kernel: igc 0000:02:00.0 eno1: NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX
Mar 09 11:56:37 titan NetworkManager[651]: <info>  [1741535797.6917] device (eno1): carrier: link connected
Mar 09 11:56:37 titan NetworkManager[651]: <info>  [1741535797.6920] device (eno1): state change: unavailable -> disconnected (reason 'carrier-changed', managed-type: 'full')
Mar 09 11:56:37 titan NetworkManager[651]: <info>  [1741535797.6930] device (eno1): Activation: starting connection 'Wired connection 1' (f46ce8aa-7cbd-3079-8385-c6fb87669bc5)
Mar 09 11:56:37 titan NetworkManager[651]: <info>  [1741535797.6931] device (eno1): state change: disconnected -> prepare (reason 'none', managed-type: 'full')
Mar 09 11:56:37 titan NetworkManager[651]: <info>  [1741535797.6933] device (eno1): state change: prepare -> config (reason 'none', managed-type: 'full')
Mar 09 11:56:37 titan NetworkManager[651]: <info>  [1741535797.7116] device (eno1): state change: config -> ip-config (reason 'none', managed-type: 'full')
Mar 09 11:56:37 titan NetworkManager[651]: <info>  [1741535797.7122] dhcp4 (eno1): activation: beginning transaction (timeout in 45 seconds)
Mar 09 11:56:39 titan NetworkManager[651]: <info>  [1741535799.4320] dhcp6 (eno1): activation: beginning transaction (timeout in 45 seconds)
Mar 09 11:56:39 titan NetworkManager[651]: <info>  [1741535799.4328] policy: set 'Wired connection 1' (eno1) as default for IPv6 routing and DNS
Mar 09 11:57:24 titan NetworkManager[651]: <info>  [1741535844.9965] device (eno1): state change: ip-config -> ip-check (reason 'none', managed-type: 'full')
Mar 09 11:57:25 titan NetworkManager[651]: <info>  [1741535845.0270] device (eno1): state change: ip-check -> secondaries (reason 'none', managed-type: 'full')
Mar 09 11:57:25 titan NetworkManager[651]: <info>  [1741535845.0271] device (eno1): state change: secondaries -> activated (reason 'none', managed-type: 'full')
Mar 09 11:57:25 titan NetworkManager[651]: <info>  [1741535845.0273] device (eno1): Activation: successful, device activated.
$

And I see no error messages.

Last edited by sgtnasty (2025-03-09 18:18:19)

seth · 2025-03-09 20:34:44

Maybe no error message, but also no dhcp4 connection.

I'd look ar firewalld and docker - the device has several altnames (ie. grepping for eno1 is certainly not enough) and although there don't seem any competetive network services, that smells like some collision sonewhere.

If it's not docker or firewalld, please post your complete system journal for the boot:

sudo journalctl -b | curl -F 'file=@-' 0x0.st

Ps, obfuscate the number that start's w/ "2600:4040", it's a publically routably IPv6 (in NJ?)

-thc · 2025-03-09 20:42:07

sgtnasty wrote:

And I see no error messages.

The problem is - as seth already mentioned - what's not there - after

Mar 09 11:56:37 titan NetworkManager[651]: <info>  [1741535797.7122] dhcp4 (eno1): activation: beginning transaction (timeout in 45 seconds)

the complete DHCPv4 transaction is missing.

Also be aware that there are possible new instances in your network that may erroneously work as a DHCPv4 server and mislead other boxes.

sgtnasty · 2025-03-10 12:16:03

Turns out it was my router. I had to cold boot it up to get any DHCPv4 working. Thanks for all the help, I really appreciate it.

seth · 2025-03-10 17:05:11

\o/
Please always remember to mark resolved threads by editing your initial posts subject - so others will know that there's no task left, but maybe a solution to find.
Thanks.

Arch Linux

#1 2025-03-09 14:35:11

[SOLVED] Help, it seems IPv4 is turned off on my server.

#2 2025-03-09 14:45:46

Re: [SOLVED] Help, it seems IPv4 is turned off on my server.

#3 2025-03-09 15:53:30

Re: [SOLVED] Help, it seems IPv4 is turned off on my server.

#4 2025-03-09 16:33:37

Re: [SOLVED] Help, it seems IPv4 is turned off on my server.

#5 2025-03-09 18:08:04

Re: [SOLVED] Help, it seems IPv4 is turned off on my server.

#6 2025-03-09 20:34:44

Re: [SOLVED] Help, it seems IPv4 is turned off on my server.

#7 2025-03-09 20:42:07

Re: [SOLVED] Help, it seems IPv4 is turned off on my server.

#8 2025-03-10 12:16:03

Re: [SOLVED] Help, it seems IPv4 is turned off on my server.

#9 2025-03-10 17:05:11

Re: [SOLVED] Help, it seems IPv4 is turned off on my server.

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