Proxmox randomly losing internet connection

omfgnuts

New Member
Jul 10, 2025
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Hey all,

I’m running Proxmox (mainly arr stack and some other media) and recently started experiencing a strange issue where the host intermittently loses internet connectivity. The only workaround I’ve found so far is to unplug the ethernet cable from the router and plug it into a different port. This restores the connection temporarily, but it drops again after a while (could be half a day, could be some hours), and I have to repeat the process.

This isn’t a configuration issue, i'm pretty sure — everything was working fine until two days ago. I haven’t changed anything on the Proxmox side (regular apt update, and the packets are not really networking related(?). To rule out the obvious, here’s the output of ip a and my /etc/network/interfaces config in case it helps, someone will definitely ask for it:

Code:
# 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: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr0 state UP group default qlen 1000
    link/ether e8:ff:1e:d7:67:45 brd ff:ff:ff:ff:ff:ff
3: wlo1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 44:38:e8:34:d3:2a brd ff:ff:ff:ff:ff:ff
    altname wlp0s20f3
4: vmbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether e8:ff:1e:d7:67:45 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.69/24 scope global vmbr0
       valid_lft forever preferred_lft forever
    inet6 fe80::eaff:1eff:fed7:6745/64 scope link
       valid_lft forever preferred_lft forever


Interfaces:
Code:
auto lo
iface lo inet loopback
iface enp1s0 inet manual
auto vmbr0
iface vmbr0 inet static

        address 192.168.1.69/24
        gateway 192.168.1.254
        bridge-ports enp1s0
        bridge-stp off
        bridge-fd 0

source /etc/network/interfaces.d/*


I'm not really sure how to debug such a weird issue. Could be a router problem? If so, how to maybe solve it?


EDIT:

Now that I'm thinking more about it, it might actually be a router problem, but what could cause it? After replugging the cable - proxmox server works ok, but to get NAS back into the action I have to restart the router. Could there be a setting on the router that might cause such an issue?
 
Last edited:
Triple check if there is an IP address conflict. ".69" must be outside of the dynamically assigned IP address range.
 
Triple check if there is an IP address conflict. ".69" must be outside of the dynamically assigned IP address range.
Was one of my first guesses. I've bind MAC to ip on the router, so there's no IP conflict 100%
 
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