Proxmox VM unreachable after adding second interface on proxmox

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prabhatlolam

New Member
May 23, 2025
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On existing proxmox server, 2 VM's are running properly with single interface, as a new requirement I have added another interface on Proxmox server for new VM creation with different IP subnet.
After adding second interface, all previous 2 VM's was unreachable although there is no changes on first interface or VM's setting.
is there any solution to add second interface without any downtime for proxmox server?
Current Proxmox version is 8.3.4
 
Is it possible that adding the new network device changed the IDs of the network cards, therefore breaking your network configuration?
 
here is the proxmox logs for your reference. When I had configured another interface, the vmbr0 entering in blocking mode and it prevents to access with existing VM's. So I have to revert the changes.



Proxmox logs:

May 23 18:00:35 Hyperv-87 pveproxy[1433]: starting 1 worker(s)

May 23 18:00:35 Hyperv-87 pveproxy[1433]: worker 3489725 started

May 23 18:01:11 Hyperv-87 pvedaemon[3488175]: <root@pam> successful auth for user 'root@pam'

May 23 18:02:02 Hyperv-87 pvedaemon[3487132]: <root@pam> starting task UPID:Hyperv-87:003540B0:07BF0F6F:68306AC2:vncproxy:200:root@pam:

May 23 18:02:02 Hyperv-87 pvedaemon[3489968]: starting vnc proxy UPID:Hyperv-87:003540B0:07BF0F6F:68306AC2:vncproxy:200:root@pam:

May 23 18:02:04 Hyperv-87 pvedaemon[3487132]: <root@pam> end task UPID:Hyperv-87:003540B0:07BF0F6F:68306AC2:vncproxy:200:root@pam: OK

May 23 18:02:06 Hyperv-87 pvedaemon[3489975]: starting termproxy UPID:Hyperv-87:003540B7:07BF10D9:68306AC5:vncshell::root@pam:

May 23 18:02:06 Hyperv-87 pvedaemon[3487132]: <root@pam> starting task UPID:Hyperv-87:003540B7:07BF10D9:68306AC5:vncshell::root@pam:

May 23 18:02:06 Hyperv-87 pvedaemon[3481138]: <root@pam> successful auth for user 'root@pam'

May 23 18:02:06 Hyperv-87 login[3489978]: pam_unix(login:session): session opened for user root(uid=0) by root(uid=0)

May 23 18:02:06 Hyperv-87 systemd-logind[1088]: New session 415 of user root.

May 23 18:02:06 Hyperv-87 systemd[1]: Started session-415.scope - Session 415 of User root.

May 23 18:02:06 Hyperv-87 login[3489983]: ROOT LOGIN on '/dev/pts/0'

May 23 18:02:31 Hyperv-87 pvedaemon[3481138]: <root@pam> successful auth for user 'root@pam'

May 23 18:03:30 Hyperv-87 systemd[1]: session-415.scope: Deactivated successfully.

May 23 18:03:30 Hyperv-87 systemd-logind[1088]: Session 415 logged out. Waiting for processes to exit.

May 23 18:03:30 Hyperv-87 systemd-logind[1088]: Removed session 415.

May 23 18:03:30 Hyperv-87 pvedaemon[3487132]: <root@pam> end task UPID:Hyperv-87:003540B7:07BF10D9:68306AC5:vncshell::root@pam: OK

May 23 18:03:30 Hyperv-87 pvedaemon[3488175]: <root@pam> starting task UPID:Hyperv-87:0035419A:07BF31DC:68306B1A:vncproxy:200:root@pam:

May 23 18:03:30 Hyperv-87 pvedaemon[3490202]: starting vnc proxy UPID:Hyperv-87:0035419A:07BF31DC:68306B1A:vncproxy:200:root@pam:

May 23 18:03:56 Hyperv-87 pveproxy[1433]: worker 3488011 finished

May 23 18:03:56 Hyperv-87 pveproxy[1433]: starting 1 worker(s)

May 23 18:03:56 Hyperv-87 pveproxy[1433]: worker 3490281 started

May 23 18:03:56 Hyperv-87 pveproxy[3490280]: got inotify poll request in wrong process - disabling inotify

May 23 18:03:57 Hyperv-87 pveproxy[3490280]: worker exit

May 23 18:03:57 Hyperv-87 pvedaemon[3488175]: <root@pam> end task UPID:Hyperv-87:0035419A:07BF31DC:68306B1A:vncproxy:200:root@pam: OK

May 23 18:03:57 Hyperv-87 pvedaemon[3488175]: <root@pam> starting task UPID:Hyperv-87:003541F0:07BF3C77:68306B35:vncproxy:201:root@pam:

May 23 18:03:57 Hyperv-87 pvedaemon[3490288]: starting vnc proxy UPID:Hyperv-87:003541F0:07BF3C77:68306B35:vncproxy:201:root@pam:

May 23 18:04:03 Hyperv-87 pvedaemon[3488175]: <root@pam> end task UPID:Hyperv-87:003541F0:07BF3C77:68306B35:vncproxy:201:root@pam: OK

May 23 18:04:09 Hyperv-87 pvedaemon[3488175]: <root@pam> starting task UPID:Hyperv-87:0035420E:07BF4148:68306B41:vncshell::root@pam:

May 23 18:04:09 Hyperv-87 pvedaemon[3490318]: starting termproxy UPID:Hyperv-87:0035420E:07BF4148:68306B41:vncshell::root@pam:

May 23 18:04:10 Hyperv-87 pvedaemon[3481138]: <root@pam> successful auth for user 'root@pam'

May 23 18:04:10 Hyperv-87 login[3490321]: pam_unix(login:session): session opened for user root(uid=0) by root(uid=0)

May 23 18:04:10 Hyperv-87 systemd-logind[1088]: New session 416 of user root.

May 23 18:04:10 Hyperv-87 systemd[1]: Started session-416.scope - Session 416 of User root.

May 23 18:04:10 Hyperv-87 login[3490326]: ROOT LOGIN on '/dev/pts/0'

May 23 18:04:19 Hyperv-87 pvedaemon[3487132]: <root@pam> starting task UPID:Hyperv-87:00354232:07BF4509:68306B4B:vncproxy:200:root@pam:

May 23 18:04:19 Hyperv-87 pvedaemon[3490354]: starting vnc proxy UPID:Hyperv-87:00354232:07BF4509:68306B4B:vncproxy:200:root@pam:

May 23 18:04:25 Hyperv-87 pvedaemon[3487132]: <root@pam> end task UPID:Hyperv-87:00354232:07BF4509:68306B4B:vncproxy:200:root@pam: OK

May 23 18:04:59 Hyperv-87 pvedaemon[3488175]: <root@pam> starting task UPID:Hyperv-87:003542A0:07BF5488:68306B73:vncproxy:201:root@pam:

May 23 18:04:59 Hyperv-87 pvedaemon[3490464]: starting vnc proxy UPID:Hyperv-87:003542A0:07BF5488:68306B73:vncproxy:201:root@pam:

May 23 18:05:02 Hyperv-87 pvedaemon[3488175]: <root@pam> end task UPID:Hyperv-87:003542A0:07BF5488:68306B73:vncproxy:201:root@pam: OK

May 23 18:05:05 Hyperv-87 pvedaemon[3481138]: <root@pam> starting task UPID:Hyperv-87:003542B8:07BF56C6:68306B79:vncshell::root@pam:

May 23 18:05:05 Hyperv-87 pvedaemon[3490488]: starting termproxy UPID:Hyperv-87:003542B8:07BF56C6:68306B79:vncshell::root@pam:

May 23 18:05:05 Hyperv-87 pvedaemon[3487132]: <root@pam> successful auth for user 'root@pam'

May 23 18:05:05 Hyperv-87 login[3490491]: pam_unix(login:session): session opened for user root(uid=0) by (uid=0)

May 23 18:05:05 Hyperv-87 systemd-logind[1088]: New session 417 of user root.

May 23 18:05:05 Hyperv-87 systemd[1]: Started session-417.scope - Session 417 of User root.

May 23 18:05:05 Hyperv-87 login[3490496]: ROOT LOGIN on '/dev/pts/1'

May 23 18:06:05 Hyperv-87 pvedaemon[3488175]: <root@pam> starting task UPID:Hyperv-87:00354362:07BF6E4B:68306BB5:vncproxy:200:root@pam:

May 23 18:06:05 Hyperv-87 pvedaemon[3490658]: starting vnc proxy UPID:Hyperv-87:00354362:07BF6E4B:68306BB5:vncproxy:200:root@pam:

May 23 18:06:08 Hyperv-87 pvedaemon[3488175]: <root@pam> end task UPID:Hyperv-87:00354362:07BF6E4B:68306BB5:vncproxy:200:root@pam: OK

May 23 18:06:12 Hyperv-87 pvedaemon[3488175]: <root@pam> starting task UPID:Hyperv-87:0035437C:07BF70FC:68306BBC:vncshell::root@pam:

May 23 18:06:12 Hyperv-87 pvedaemon[3490684]: starting termproxy UPID:Hyperv-87:0035437C:07BF70FC:68306BBC:vncshell::root@pam:

May 23 18:06:12 Hyperv-87 pvedaemon[3487132]: <root@pam> successful auth for user 'root@pam'

May 23 18:06:12 Hyperv-87 login[3490687]: pam_unix(login:session): session opened for user root(uid=0) by (uid=0)

May 23 18:06:12 Hyperv-87 systemd-logind[1088]: New session 418 of user root.

May 23 18:06:12 Hyperv-87 systemd[1]: Started session-418.scope - Session 418 of User root.

May 23 18:06:12 Hyperv-87 login[3490692]: ROOT LOGIN on '/dev/pts/2'

May 23 18:07:05 Hyperv-87 systemd[1]: session-418.scope: Deactivated successfully.

May 23 18:07:05 Hyperv-87 systemd-logind[1088]: Session 418 logged out. Waiting for processes to exit.

May 23 18:07:05 Hyperv-87 systemd-logind[1088]: Removed session 418.

May 23 18:07:05 Hyperv-87 pvedaemon[3488175]: <root@pam> end task UPID:Hyperv-87:0035437C:07BF70FC:68306BBC:vncshell::root@pam: OK

May 23 18:07:07 Hyperv-87 systemd[1]: session-416.scope: Deactivated successfully.

May 23 18:07:07 Hyperv-87 systemd-logind[1088]: Session 416 logged out. Waiting for processes to exit.

May 23 18:07:07 Hyperv-87 systemd-logind[1088]: Removed session 416.

May 23 18:07:07 Hyperv-87 pvedaemon[3488175]: <root@pam> end task UPID:Hyperv-87:0035420E:07BF4148:68306B41:vncshell::root@pam: OK

May 23 18:07:29 Hyperv-87 pvedaemon[3481138]: <root@pam> starting task UPID:Hyperv-87:00354454:07BF8F2D:68306C09:srvreload:networking:root@pam:

May 23 18:07:29 Hyperv-87 kernel: vmbr1: port 1(ens3f2) entered disabled state

May 23 18:07:29 Hyperv-87 systemd[1]: Reloading postfix@-.service - Postfix Mail Transport Agent (instance -)...

May 23 18:07:29 Hyperv-87 postfix[3490928]: Postfix is using backwards-compatible default settings

May 23 18:07:29 Hyperv-87 postfix[3490928]: See http://www.postfix.org/COMPATIBILITY_README.html for details

May 23 18:07:29 Hyperv-87 postfix[3490928]: To disable backwards compatibility use "postconf compatibility_level=3.6" and "postfix reload"

May 23 18:07:29 Hyperv-87 postfix/postfix-script[3490934]: refreshing the Postfix mail system

May 23 18:07:29 Hyperv-87 postfix/master[1377]: reload -- version 3.7.11, configuration /etc/postfix

May 23 18:07:29 Hyperv-87 systemd[1]: Reloaded postfix@-.service - Postfix Mail Transport Agent (instance -).

May 23 18:07:29 Hyperv-87 systemd[1]: Reloading postfix.service - Postfix Mail Transport Agent...

May 23 18:07:29 Hyperv-87 systemd[1]: Reloaded postfix.service - Postfix Mail Transport Agent.

May 23 18:07:29 Hyperv-87 kernel: tg3 0000:d8:00.2 ens3f2: left allmulticast mode

May 23 18:07:29 Hyperv-87 kernel: tg3 0000:d8:00.2 ens3f2: left promiscuous mode

May 23 18:07:29 Hyperv-87 kernel: vmbr1: port 1(ens3f2) entered disabled state

May 23 18:07:30 Hyperv-87 systemd[1]: Reloading postfix@-.service - Postfix Mail Transport Agent (instance -)...

May 23 18:07:30 Hyperv-87 postfix[3490972]: Postfix is using backwards-compatible default settings

May 23 18:07:30 Hyperv-87 postfix[3490972]: See http://www.postfix.org/COMPATIBILITY_README.html for details

May 23 18:07:30 Hyperv-87 postfix[3490972]: To disable backwards compatibility use "postconf compatibility_level=3.6" and "postfix reload"

May 23 18:07:30 Hyperv-87 postfix/postfix-script[3490978]: refreshing the Postfix mail system

May 23 18:07:30 Hyperv-87 postfix/master[1377]: reload -- version 3.7.11, configuration /etc/postfix

May 23 18:07:30 Hyperv-87 systemd[1]: Reloaded postfix@-.service - Postfix Mail Transport Agent (instance -).

May 23 18:07:30 Hyperv-87 systemd[1]: Reloading postfix.service - Postfix Mail Transport Agent...

May 23 18:07:30 Hyperv-87 systemd[1]: Reloaded postfix.service - Postfix Mail Transport Agent.

May 23 18:07:30 Hyperv-87 kernel: vmbr0: the hash_elasticity option has been deprecated and is always 16

May 23 18:07:30 Hyperv-87 systemd[1]: Reloading postfix@-.service - Postfix Mail Transport Agent (instance -)...

May 23 18:07:30 Hyperv-87 postfix[3491004]: Postfix is using backwards-compatible default settings

May 23 18:07:30 Hyperv-87 postfix[3491004]: See http://www.postfix.org/COMPATIBILITY_README.html for details

May 23 18:07:30 Hyperv-87 postfix[3491004]: To disable backwards compatibility use "postconf compatibility_level=3.6" and "postfix reload"

May 23 18:07:30 Hyperv-87 postfix/postfix-script[3491010]: refreshing the Postfix mail system

May 23 18:07:30 Hyperv-87 postfix/master[1377]: reload -- version 3.7.11, configuration /etc/postfix

May 23 18:07:30 Hyperv-87 systemd[1]: Reloaded postfix@-.service - Postfix Mail Transport Agent (instance -).

May 23 18:07:30 Hyperv-87 systemd[1]: Reloading postfix.service - Postfix Mail Transport Agent...

May 23 18:07:30 Hyperv-87 systemd[1]: Reloaded postfix.service - Postfix Mail Transport Agent.

May 23 18:07:30 Hyperv-87 pvedaemon[3481138]: <root@pam> end task UPID:Hyperv-87:00354454:07BF8F2D:68306C09:srvreload:networking:root@pam: OK

May 23 18:07:34 Hyperv-87 pvedaemon[3487132]: <root@pam> starting task UPID:Hyperv-87:003544DD:07BF9151:68306C0E:vncshell::root@pam:

May 23 18:07:34 Hyperv-87 pvedaemon[3491037]: starting termproxy UPID:Hyperv-87:003544DD:07BF9151:68306C0E:vncshell::root@pam:

May 23 18:07:34 Hyperv-87 pvedaemon[3481138]: <root@pam> successful auth for user 'root@pam'

May 23 18:07:35 Hyperv-87 login[3491040]: pam_unix(login:session): session opened for user root(uid=0) by root(uid=0)

May 23 18:07:35 Hyperv-87 systemd-logind[1088]: New session 419 of user root.

May 23 18:07:35 Hyperv-87 systemd[1]: Started session-419.scope - Session 419 of User root.

May 23 18:07:35 Hyperv-87 login[3491045]: ROOT LOGIN on '/dev/pts/0'

May 23 18:08:05 Hyperv-87 systemd[1]: session-419.scope: Deactivated successfully.

May 23 18:08:05 Hyperv-87 systemd-logind[1088]: Session 419 logged out. Waiting for processes to exit.

May 23 18:08:05 Hyperv-87 systemd-logind[1088]: Removed session 419.

May 23 18:08:05 Hyperv-87 pvedaemon[3487132]: <root@pam> end task UPID:Hyperv-87:003544DD:07BF9151:68306C0E:vncshell::root@pam: OK

May 23 18:08:32 Hyperv-87 pvedaemon[3488175]: <root@pam> successful auth for user 'root@pam'

May 23 18:09:41 Hyperv-87 kernel: tg3 0000:d8:00.2 ens3f2: Link is down

May 23 18:10:57 Hyperv-87 pvedaemon[3481138]: <root@pam> successful auth for user 'root@pam'

May 23 18:11:08 Hyperv-87 pvedaemon[3488175]: <root@pam> update VM 200: -net0 virtio,bridge=vmbr0,firewall=1

May 23 18:11:09 Hyperv-87 kernel: tap200i0: left allmulticast mode

May 23 18:11:09 Hyperv-87 kernel: fwbr200i0: port 2(tap200i0) entered disabled state

May 23 18:11:09 Hyperv-87 kernel: fwbr200i0: port 1(fwln200i0) entered disabled state

May 23 18:11:09 Hyperv-87 kernel: fwln200i0 (unregistering): left allmulticast mode

May 23 18:11:09 Hyperv-87 kernel: fwln200i0 (unregistering): left promiscuous mode

May 23 18:11:09 Hyperv-87 kernel: fwbr200i0: port 1(fwln200i0) entered disabled state

May 23 18:11:10 Hyperv-87 kernel: tap200i0: entered promiscuous mode

May 23 18:11:10 Hyperv-87 kernel: vmbr0: port 2(fwpr200p0) entered blocking state

May 23 18:11:10 Hyperv-87 kernel: vmbr0: port 2(fwpr200p0) entered disabled state

May 23 18:11:10 Hyperv-87 kernel: fwpr200p0: entered allmulticast mode

May 23 18:11:10 Hyperv-87 kernel: fwpr200p0: entered promiscuous mode

May 23 18:11:10 Hyperv-87 kernel: vmbr0: port 2(fwpr200p0) entered blocking state

May 23 18:11:10 Hyperv-87 kernel: vmbr0: port 2(fwpr200p0) entered forwarding state

May 23 18:11:10 Hyperv-87 kernel: fwbr200i0: port 1(fwln200i0) entered blocking state

May 23 18:11:10 Hyperv-87 kernel: fwbr200i0: port 1(fwln200i0) entered disabled state

May 23 18:11:10 Hyperv-87 kernel: fwln200i0: entered allmulticast mode

May 23 18:11:10 Hyperv-87 kernel: fwln200i0: entered promiscuous mode

May 23 18:11:10 Hyperv-87 kernel: fwbr200i0: port 1(fwln200i0) entered blocking state

May 23 18:11:10 Hyperv-87 kernel: fwbr200i0: port 1(fwln200i0) entered forwarding state

May 23 18:11:10 Hyperv-87 kernel: fwbr200i0: port 2(tap200i0) entered blocking state

May 23 18:11:10 Hyperv-87 kernel: fwbr200i0: port 2(tap200i0) entered disabled state

May 23 18:11:10 Hyperv-87 kernel: tap200i0: entered allmulticast mode

May 23 18:11:10 Hyperv-87 kernel: fwbr200i0: port 2(tap200i0) entered blocking state

May 23 18:11:10 Hyperv-87 kernel: fwbr200i0: port 2(tap200i0) entered forwarding state

May 23 18:11:17 Hyperv-87 pvedaemon[3487132]: <root@pam> update VM 201: -net0 virtio,bridge=vmbr0

May 23 18:11:19 Hyperv-87 kernel: tap201i0: entered promiscuous mode

May 23 18:11:19 Hyperv-87 kernel: vmbr0: port 3(tap201i0) entered blocking state

May 23 18:11:19 Hyperv-87 kernel: vmbr0: port 3(tap201i0) entered disabled state

May 23 18:11:19 Hyperv-87 kernel: tap201i0: entered allmulticast mode

May 23 18:11:19 Hyperv-87 kernel: vmbr0: port 3(tap201i0) entered blocking state

May 23 18:11:19 Hyperv-87 kernel: vmbr0: port 3(tap201i0) entered forwarding state


Thanks in advance.
 
What exactly did you try? Add another bridge to the network configuration? How did the configuration that didn't work look like?

Code: 
cat /etc/network/interfaces
ip a
 
yes, I have another bridge to the network configuration with "vmbr1" name. After adding another bridge, existing VM's unable to communicate with proxmox host and even gateway IP. It gives an error as "no route to host"

I am trying to create another bridge for new VM's with different IP Subnet and it is disturbing existing VM's communication.
As it is production server's, I can't do more experiments on this.
I am arranging testing server to check the same issue.
 

Attachments

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  • interface screenshot.jpg
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Yes please, in order to understand the problem I'd need to see the configuration that you tried to apply - otherwise it is hard to tell what went wrong.

prabhatlolam said:
After adding another bridge, existing VM's unable to communicate with proxmox host and even gateway IP. It gives an error as "no route to host"
Click to expand...
How does the network setup of the VMs look like?
 
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