Fedora server becomes unreachable after I put my remote PC that is connected to the Fedora server

clear · June 30, 2023, 1:00pm

I’m very perplexed as to why this happens, the server works just fine on it’s on, but the moment I’m connected to it and I put my remote PC to sleep, my fedora server refuses to allow any further attempt to remote connection from my remote PC (pc_1), I can ping it and ssh to it from another remote PC (pc_2).

This seem to have started to happen after I updated fedora (I’ve had the server turn off for about 6 months).

The only noteworthy log message that might be related is this:
[2023/06/30 14:57:25.437850, 0] ../../source3/smbd/server.c:1746(main)

Kernel version:
Linux 6.3.8-200.fc38.x86_64 #1 SMP PREEMPT_DYNAMIC Thu Jun 15 02:15:40 UTC 2023 x86_64 GNU/Linux

Network Manager:
NetworkManager x86_64 1:1.42.8-1.fc38

Jun 30 15:51:54 rumia NetworkManager[5093]: <info>  [1688133114.9226] device (lo): Activation: successful, device activated.
Jun 30 15:51:54 rumia NetworkManager[5093]: <info>  [1688133114.9237] device (lxdbr0): state change: secondaries -> activated (reason 'none', sys-iface-state: 'ext>
Jun 30 15:51:54 rumia NetworkManager[5093]: <info>  [1688133114.9243] manager: NetworkManager state is now CONNECTED_LOCAL
Jun 30 15:51:54 rumia NetworkManager[5093]: <info>  [1688133114.9249] device (lxdbr0): Activation: successful, device activated.
Jun 30 15:51:54 rumia NetworkManager[5093]: <info>  [1688133114.9259] device (enp2s0): state change: ip-check -> secondaries (reason 'none', sys-iface-state: 'assu>
Jun 30 15:51:54 rumia NetworkManager[5093]: <info>  [1688133114.9264] device (enp2s0): state change: secondaries -> activated (reason 'none', sys-iface-state: 'ass>
Jun 30 15:51:54 rumia NetworkManager[5093]: <info>  [1688133114.9270] manager: NetworkManager state is now CONNECTED_SITE
Jun 30 15:51:54 rumia NetworkManager[5093]: <info>  [1688133114.9276] device (enp2s0): Activation: successful, device activated.
Jun 30 15:51:54 rumia NetworkManager[5093]: <info>  [1688133114.9286] manager: NetworkManager state is now CONNECTED_GLOBAL
Jun 30 15:51:54 rumia NetworkManager[5093]: <info>  [1688133114.9326] manager: startup complete

vgaetera · June 30, 2023, 2:19pm

Fully upgrade and reboot the client, server, and router.
Check if you can reliably reproduce the issue and confirm with tcpdump on the server that the original client can still reach it.

clear · June 30, 2023, 2:47pm

I’ve updated/rebooted the server, client and router.

I can reproduce it by doing the following:

Have the latest up to date Fedora server 38
Connect to the server via ssh, samba or cockpit
Put the pc connected to the server to sleep
Awake it and the server won’t allow connections from the pc that was put to sleep
Restart NetworkManager ‘resolves’ it
Then you can do this over and over again.

I’ll admit I’m not very familiar with tcpdump so I ran:
sudo tcpdump -i enp2s0 -vnnn port 22
and:
sudo tcpdump -i enp2s0 -vnnn port 9090
With both - when pc_1 connects after an awake it does not even show up on tcpdump, if I reset NetworkManager it works just like any other connection.
Port 9090:

16:58:27.691725 IP (tos 0x0, ttl 64, id 38962, offset 0, flags [DF], proto TCP (6), length 561)
    server_ip.9090 > pc_1_ip.56635: Flags [P.], cksum 0x86ff (incorrect -> 0x2944), seq 766149:766670, ack 56073, win 63948, length 521
16:58:27.695640 IP (tos 0x0, ttl 128, id 34837, offset 0, flags [DF], proto TCP (6), length 190)
    pc_1_ip.56635 > server_ip.9090: Flags [P.], cksum 0x8eb4 (correct), seq 56073:56223, ack 766670, win 63605, length 150
16:58:27.695730 IP (tos 0x0, ttl 128, id 34838, offset 0, flags [DF], proto TCP (6), length 189)
    pc_1_ip.56635 > server_ip.9090: Flags [P.], cksum 0x69d2 (correct), seq 56223:56372, ack 766670, win 63605, length 149
16:58:27.695820 IP (tos 0x0, ttl 64, id 38963, offset 0, flags [DF], proto TCP (6), length 40)
    server_ip.9090 > pc_1_ip.56635: Flags [.], cksum 0x4a29 (correct), ack 56372, win 63948, length 0
16:58:27.695935 IP (tos 0x0, ttl 128, id 34839, offset 0, flags [DF], proto TCP (6), length 188)
    pc_1_ip.56635 > server_ip.9090: Flags [P.], cksum 0xa316 (correct), seq 56372:56520, ack 766670, win 63605, length 148
16:58:27.696000 IP (tos 0x0, ttl 128, id 34840, offset 0, flags [DF], proto TCP (6), length 111)
    pc_1_ip.56635 > server_ip.9090: Flags [P.], cksum 0xe24b (correct), seq 56520:56591, ack 766670, win 63605, length 71

Port 22:

17:04:47.888111 IP (tos 0x0, ttl 128, id 43825, offset 0, flags [DF], proto TCP (6), length 48)
    pc_1_ip.56941 > server_ip.22: Flags [S], cksum 0x5086 (correct), seq 3984582344, win 64240, options [mss 1460,nop,nop,sackOK], length 0
17:04:47.888199 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 48)
    server_ip.22 > pc_1_ip.56941: Flags [S.], cksum 0x84fe (incorrect -> 0xd3b4), seq 1945241806, ack 3984582345, win 64240, options [mss 1460,nop,nop,sackOK], length 0
17:04:47.888360 IP (tos 0x0, ttl 128, id 43826, offset 0, flags [DF], proto TCP (6), length 40)
    pc_1_ip.56941 > server_ip.22: Flags [.], cksum 0x0079 (correct), ack 1, win 64240, length 0
17:04:47.889954 IP (tos 0x0, ttl 128, id 43827, offset 0, flags [DF], proto TCP (6), length 73)
    pc_1_ip.56941 > server_ip.22: Flags [P.], cksum 0xbd33 (correct), seq 1:34, ack 1, win 64240, length 33: SSH: SSH-2.0-OpenSSH_for_Windows_8.1
17:04:47.890011 IP (tos 0x0, ttl 64, id 33304, offset 0, flags [DF], proto TCP (6), length 40)
    server_ip.22 > pc_1_ip.56941: Flags [.], cksum 0x0079 (correct), ack 34, win 64207, length 0
17:04:47.904271 IP (tos 0x0, ttl 64, id 33305, offset 0, flags [DF], proto TCP (6), length 61)
    server_ip.22 > pc_1_ip.56941: Flags [P.], cksum 0x850b (incorrect -> 0x3eb3), seq 1:22, ack 34, win 64207, length 21: SSH: SSH-2.0-OpenSSH_9.0
17:04:47.906697 IP (tos 0x0, ttl 128, id 43828, offset 0, flags [DF], proto TCP (6), length 1432)
    pc_1_ip.56941 > server_ip.22: Flags [P.], cksum 0x694d (correct), seq 34:1426, ack 22, win 64219, length 1392
17:04:47.907321 IP (tos 0x0, ttl 64, id 33306, offset 0, flags [DF], proto TCP (6), length 976)
    server_ip.22 > pc_1_ip.56941: Flags [P.], cksum 0x889e (incorrect -> 0xb6ff), seq 22:958, ack 1426, win 64032, length 936
17:04:47.909389 IP (tos 0x0, ttl 128, id 43829, offset 0, flags [DF], proto TCP (6), length 88)
    pc_1_ip.56941 > server_ip.22: Flags [P.], cksum 0x77b1 (correct), seq 1426:1474, ack 958, win 63283, length 48
17:04:47.914003 IP (tos 0x0, ttl 64, id 33307, offset 0, flags [DF], proto TCP (6), length 636)
    server_ip.22 > pc_1_ip.56941: Flags [P.], cksum 0x874a (incorrect -> 0xfb98), seq 958:1554, ack 1474, win 64032, length 596
17:04:47.922372 IP (tos 0x0, ttl 128, id 43834, offset 0, flags [DF], proto TCP (6), length 56)
    pc_1_ip.56941 > server_ip.22: Flags [P.], cksum 0xea6d (correct), seq 1474:1490, ack 1554, win 64240, length 16
17:04:47.962546 IP (tos 0x0, ttl 64, id 33308, offset 0, flags [DF], proto TCP (6), length 40)
    server_ip.22 > pc_1_ip.56941: Flags [.], cksum 0xf566 (correct), ack 1490, win 64032, length 0
17:04:47.962910 IP (tos 0x0, ttl 128, id 43836, offset 0, flags [DF], proto TCP (6), length 84)
    pc_1_ip.56941 > server_ip.22: Flags [P.], cksum 0xa27a (correct), seq 1490:1534, ack 1554, win 64240, length 44
17:04:47.962960 IP (tos 0x0, ttl 64, id 33309, offset 0, flags [DF], proto TCP (6), length 40)
    server_ip.22 > pc_1_ip.56941: Flags [.], cksum 0xf53a (correct), ack 1534, win 64032, length 0
17:04:47.963121 IP (tos 0x0, ttl 64, id 33310, offset 0, flags [DF], proto TCP (6), length 84)
    server_ip.22 > pc_1_ip.56941: Flags [P.], cksum 0x8522 (incorrect -> 0x2a48), seq 1554:1598, ack 1534, win 64032, length 44
17:04:47.963426 IP (tos 0x0, ttl 128, id 43837, offset 0, flags [DF], proto TCP (6), length 108)
    pc_1_ip.56941 > server_ip.22: Flags [P.], cksum 0x33b3 (correct), seq 1534:1602, ack 1598, win 64196, length 68
17:04:47.971570 IP (tos 0x0, ttl 64, id 33311, offset 0, flags [DF], proto TCP (6), length 108)
    server_ip.22 > pc_1_ip.56941: Flags [P.], cksum 0x853a (incorrect -> 0x7ca6), seq 1598:1666, ack 1602, win 64032, length 68
17:04:47.971853 IP (tos 0x0, ttl 128, id 43838, offset 0, flags [DF], proto TCP (6), length 412)
    pc_1_ip.56941 > server_ip.22: Flags [P.], cksum 0x5ec5 (correct), seq 1602:1974, ack 1666, win 64128, length 372
17:04:47.977515 IP (tos 0x0, ttl 64, id 33312, offset 0, flags [DF], proto TCP (6), length 108)
    server_ip.22 > pc_1_ip.56941: Flags [P.], cksum 0x853a (incorrect -> 0xbdbb), seq 1666:1734, ack 1974, win 64032, length 68
17:04:48.020032 IP (tos 0x0, ttl 128, id 43839, offset 0, flags [DF], proto TCP (6), length 40)
    pc_1_ip.56941 > server_ip.22: Flags [.], cksum 0xf2b2 (correct), ack 1734, win 64060, length 0
17:04:51.421547 IP (tos 0x0, ttl 128, id 43916, offset 0, flags [DF], proto TCP (6), length 188)
    pc_1_ip.56941 > server_ip.22: Flags [P.], cksum 0x6668 (correct), seq 1974:2122, ack 1734, win 64060, length 148
17:04:51.433527 IP (tos 0x0, ttl 64, id 33313, offset 0, flags [DF], proto TCP (6), length 68)
    server_ip.22 > pc_1_ip.56941: Flags [P.], cksum 0x8512 (incorrect -> 0xf0d8), seq 1734:1762, ack 2122, win 64032, length 28
17:04:51.434351 IP (tos 0x0, ttl 128, id 43917, offset 0, flags [DF], proto TCP (6), length 152)
    pc_1_ip.56941 > server_ip.22: Flags [P.], cksum 0x0168 (correct), seq 2122:2234, ack 1762, win 64032, length 112
17:04:51.473022 IP (tos 0x0, ttl 64, id 33314, offset 0, flags [DF], proto TCP (6), length 668)
    server_ip.22 > pc_1_ip.56941: Flags [P.], cksum 0x876a (incorrect -> 0x6616), seq 1762:2390, ack 2234, win 64032, length 628
17:04:51.522854 IP (tos 0x0, ttl 128, id 43940, offset 0, flags [DF], proto TCP (6), length 40)
    pc_1_ip.56941 > server_ip.22: Flags [.], cksum 0xf1ae (correct), ack 2390, win 63404, length 0
17:04:51.522896 IP (tos 0x0, ttl 64, id 33315, offset 0, flags [DF], proto TCP (6), length 84)
    server_ip.22 > pc_1_ip.56941: Flags [P.], cksum 0x8522 (incorrect -> 0x529c), seq 2390:2434, ack 2234, win 64032, length 44
17:04:51.524650 IP (tos 0x0, ttl 128, id 43941, offset 0, flags [DF], proto TCP (6), length 176)
    pc_1_ip.56941 > server_ip.22: Flags [P.], cksum 0x69cc (correct), seq 2234:2370, ack 2434, win 63360, length 136
17:04:51.533012 IP (tos 0x48, ttl 64, id 33316, offset 0, flags [DF], proto TCP (6), length 148)
    server_ip.22 > pc_1_ip.56941: Flags [P.], cksum 0x8562 (incorrect -> 0xa4c3), seq 2434:2542, ack 2370, win 64032, length 108
17:04:51.533076 IP (tos 0x48, ttl 64, id 33317, offset 0, flags [DF], proto TCP (6), length 204)
    server_ip.22 > pc_1_ip.56941: Flags [P.], cksum 0x859a (incorrect -> 0x0d0c), seq 2542:2706, ack 2370, win 64032, length 164
17:04:51.533183 IP (tos 0x0, ttl 128, id 43942, offset 0, flags [DF], proto TCP (6), length 40)
    pc_1_ip.56941 > server_ip.22: Flags [.], cksum 0xf126 (correct), ack 2706, win 63088, length 0
17:04:51.745620 IP (tos 0x48, ttl 64, id 33318, offset 0, flags [DF], proto TCP (6), length 92)
    server_ip.22 > pc_1_ip.56941: Flags [P.], cksum 0x852a (incorrect -> 0xe46f), seq 2706:2758, ack 2370, win 64032, length 52
17:04:51.745861 IP (tos 0x48, ttl 64, id 33319, offset 0, flags [DF], proto TCP (6), length 100)
    server_ip.22 > pc_1_ip.56941: Flags [P.], cksum 0x8532 (incorrect -> 0x251b), seq 2758:2818, ack 2370, win 64032, length 60
17:04:51.746020 IP (tos 0x0, ttl 128, id 43975, offset 0, flags [DF], proto TCP (6), length 40)
    pc_1_ip.56941 > server_ip.22: Flags [.], cksum 0xf126 (correct), ack 2818, win 62976, length 0

Network config for enp2s0:

[connection]
id=enp2s0
uuid=3cc69273-af22-3a51-a840-55d9fda32ff1
type=ethernet
autoconnect-priority=-999
interface-name=enp2s0
timestamp=1688132646

[ethernet]

[ipv4]
address1=server_id/32,router_ip
method=auto

[ipv6]
addr-gen-mode=eui64
method=auto

[proxy]

vgaetera · June 30, 2023, 4:14pm

The netmask is typically something like /24.

clear · June 30, 2023, 4:22pm

Changed it to /24 and restarted NetworkManager, still occurs.

vgaetera · June 30, 2023, 4:24pm

IPv4 specified to auto means to use DHCP, then why did you set up a static IP?

clear · June 30, 2023, 4:47pm

I tried setting a manual IP before to see if dhcp had something to do with it, I forgot remove the line.