VM not passing traffic through SFP+ nic

stakey · Friday at 18:19

Hi there,

I've searched the forums, but I'm not coming up with any article on this and I'm hoping someone can help. I'm working with a ProxMox server and have a vm set up for our new Sangoma call manager server. The server has multiple nics and 2 of which are sfp+.

When I configure an IP address on one of the SFP+ ports I can ping it from my core it's connected to and load the management window perfectly fine so I know I have connectivity from the SFP+ port to the core. When I switch the network settings on my VM from the copper connection to the sfp one it doesn't pass any traffic. I also have tried building a temporary VM pointing to that SFP+ port to see if it was a vm issue and it doesn't pass traffic through it either, but moving to the copper connection makes it start passing traffic. Both of these ports are on the same vlan.

Hopefully this is just something simple I'm missing as it's very confusing as to why this is happening.

The HyperVisor version is 8.4.0.

My apologies in advance if this has been answered previously and I've missed it.

Thanks,

Marc

Onslow · Friday at 20:13

Welcome, stakey!
Hard to guess unless you post the full details of network settings of the host and of the VM

.

From the host:

cat /etc/network/interfaces
ip a
ip route

qm config 100 | grep net
(assuming that the VM id is 100).

And the network settings from the VM.

In both situations: when it works and when it doesn't.

The commands and the outputs please post in the CODE tags (click < / > button in the upper menu).

stakey · Friday at 20:46

Code:

Linux bcscallmgrproxmox 6.8.12-9-pve #1 SMP PREEMPT_DYNAMIC PMX 6.8.12-9 (2025-03-16T19:18Z) x86_64

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Thu Aug 28 14:30:36 EDT 2025 on pts/0
root@bcscallmgrproxmox:~# cat /etc/network/interfaces
# network interface settings; autogenerated
# Please do NOT modify this file directly, unless you know what
# you're doing.
#
# If you want to manage parts of the network configuration manually,
# please utilize the 'source' or 'source-directory' directives to do
# so.
# PVE will preserve these directives, but will NOT read its network
# configuration from sourced files, so do not attempt to move any of
# the PVE managed interfaces into external files!

auto lo
iface lo inet loopback

iface ens81f0np0 inet manual

auto ens83f1np1
iface ens83f1np1 inet manual

iface enx76c6b3d1c591 inet manual

iface ens38f0 inet manual

iface ens38f1 inet manual

iface ens38f2 inet manual

iface ens38f3 inet manual

iface ens81f1np1 inet manual

auto ens83f0np0
iface ens83f0np0 inet manual

auto vmbr0
iface vmbr0 inet static
        address 10.16.0.4/21
        bridge-ports ens81f0np0
        bridge-stp off
        bridge-fd 0

auto vmbr1
iface vmbr1 inet static
        address 192.168.0.68/24
        bridge-ports ens83f0np0
        bridge-stp off
        bridge-fd 0

auto vmbr2
iface vmbr2 inet manual
        bridge-ports ens81f1np1
        bridge-stp off
        bridge-fd 0

auto vmbr3
iface vmbr3 inet static
        address 10.16.0.5/21
        gateway 10.16.0.1
        bridge-ports ens83f1np1
        bridge-stp off
        bridge-fd 0

source /etc/network/interfaces.d/*
root@bcscallmgrproxmox:~# 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: ens81f0np0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr0 state UP group default qlen 1000
    link/ether a0:36:bc:cd:92:e7 brd ff:ff:ff:ff:ff:ff
    altname enp23s0f0np0
3: ens81f1np1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr2 state UP group default qlen 1000
    link/ether a0:36:bc:cd:92:e8 brd ff:ff:ff:ff:ff:ff
    altname enp23s0f1np1
4: ens38f0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 50:7c:6f:70:2a:b4 brd ff:ff:ff:ff:ff:ff
    altname enp177s0f0
5: ens38f1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 50:7c:6f:70:2a:b5 brd ff:ff:ff:ff:ff:ff
    altname enp177s0f1
6: ens38f2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 50:7c:6f:70:2a:b6 brd ff:ff:ff:ff:ff:ff
    altname enp177s0f2
7: ens83f0np0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr1 state UP group default qlen 1000
    link/ether 40:a6:b7:c8:da:84 brd ff:ff:ff:ff:ff:ff
    altname enp24s0f0np0
8: ens38f3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 50:7c:6f:70:2a:b7 brd ff:ff:ff:ff:ff:ff
    altname enp177s0f3
9: ens83f1np1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr3 state UP group default qlen 1000
    link/ether 40:a6:b7:c8:da:85 brd ff:ff:ff:ff:ff:ff
    altname enp24s0f1np1
10: enx76c6b3d1c591: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 76:c6:b3:d1:c5:91 brd ff:ff:ff:ff:ff:ff
11: vmbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether a0:36:bc:cd:92:e7 brd ff:ff:ff:ff:ff:ff
    inet 10.16.0.4/21 scope global vmbr0
       valid_lft forever preferred_lft forever
    inet6 fe80::a236:bcff:fecd:92e7/64 scope link
       valid_lft forever preferred_lft forever
12: vmbr1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 40:a6:b7:c8:da:84 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.68/24 scope global vmbr1
       valid_lft forever preferred_lft forever
    inet6 fe80::42a6:b7ff:fec8:da84/64 scope link
       valid_lft forever preferred_lft forever
13: vmbr2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether a0:36:bc:cd:92:e8 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::a236:bcff:fecd:92e8/64 scope link
       valid_lft forever preferred_lft forever
1367: tap100i0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master fwbr100i0 state UNKNOWN group default qlen 1000
    link/ether fe:4e:12:17:bf:18 brd ff:ff:ff:ff:ff:ff
1371: tap100i1: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master fwbr100i1 state UNKNOWN group default qlen 1000
    link/ether 72:8e:5d:43:70:a4 brd ff:ff:ff:ff:ff:ff
1387: fwbr100i1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether a6:ea:5d:d5:5a:25 brd ff:ff:ff:ff:ff:ff
1388: fwpr100p1@fwln100i1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr2 state UP group default qlen 1000
    link/ether b6:f9:1c:42:2a:e9 brd ff:ff:ff:ff:ff:ff
1389: fwln100i1@fwpr100p1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master fwbr100i1 state UP group default qlen 1000
    link/ether a6:ea:5d:d5:5a:25 brd ff:ff:ff:ff:ff:ff
1393: vmbr3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 40:a6:b7:c8:da:85 brd ff:ff:ff:ff:ff:ff
    inet 10.16.0.5/21 scope global vmbr3
       valid_lft forever preferred_lft forever
    inet6 fe80::42a6:b7ff:fec8:da85/64 scope link
       valid_lft forever preferred_lft forever
1419: fwbr100i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether e6:ee:98:36:9c:37 brd ff:ff:ff:ff:ff:ff
1420: fwpr100p0@fwln100i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr0 state UP group default qlen 1000
    link/ether 0e:87:95:98:b4:d9 brd ff:ff:ff:ff:ff:ff
1421: fwln100i0@fwpr100p0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master fwbr100i0 state UP group default qlen 1000
    link/ether e6:ee:98:36:9c:37 brd ff:ff:ff:ff:ff:ff
root@bcscallmgrproxmox:~# ip route
default via 10.16.0.1 dev vmbr3 proto kernel onlink
10.16.0.0/21 dev vmbr0 proto kernel scope link src 10.16.0.4
10.16.0.0/21 dev vmbr3 proto kernel scope link src 10.16.0.5
192.168.0.0/24 dev vmbr1 proto kernel scope link src 192.168.0.68
root@bcscallmgrproxmox:~# qm config 100 | grep net
boot: order=sata0;ide2;net0
net0: virtio=BC:24:11:B3:40:05,bridge=vmbr0,firewall=1
net1: virtio=BC:24:11:8A:0F:B5,bridge=vmbr2,firewall=1
root@bcscallmgrproxmox:~# ^C
root@bcscallmgrproxmox:~#

stakey · Friday at 20:46

Code:

Linux bcscallmgrproxmox 6.8.12-9-pve #1 SMP PREEMPT_DYNAMIC PMX 6.8.12-9 (2025-03-16T19:18Z) x86_64

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Fri Oct 31 15:39:21 EDT 2025 on pts/0
root@bcscallmgrproxmox:~# cat /etc/network/interfaces
# network interface settings; autogenerated
# Please do NOT modify this file directly, unless you know what
# you're doing.
#
# If you want to manage parts of the network configuration manually,
# please utilize the 'source' or 'source-directory' directives to do
# so.
# PVE will preserve these directives, but will NOT read its network
# configuration from sourced files, so do not attempt to move any of
# the PVE managed interfaces into external files!

auto lo
iface lo inet loopback

iface ens81f0np0 inet manual

auto ens83f1np1
iface ens83f1np1 inet manual

iface enx76c6b3d1c591 inet manual

iface ens38f0 inet manual

iface ens38f1 inet manual

iface ens38f2 inet manual

iface ens38f3 inet manual

iface ens81f1np1 inet manual

auto ens83f0np0
iface ens83f0np0 inet manual

auto vmbr0
iface vmbr0 inet static
        address 10.16.0.4/21
        bridge-ports ens81f0np0
        bridge-stp off
        bridge-fd 0

auto vmbr1
iface vmbr1 inet static
        address 192.168.0.68/24
        bridge-ports ens83f0np0
        bridge-stp off
        bridge-fd 0

auto vmbr2
iface vmbr2 inet manual
        bridge-ports ens81f1np1
        bridge-stp off
        bridge-fd 0

auto vmbr3
iface vmbr3 inet static
        address 10.16.0.5/21
        gateway 10.16.0.1
        bridge-ports ens83f1np1
        bridge-stp off
        bridge-fd 0

source /etc/network/interfaces.d/*
root@bcscallmgrproxmox:~# 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: ens81f0np0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr0 state UP group default qlen 1000
    link/ether a0:36:bc:cd:92:e7 brd ff:ff:ff:ff:ff:ff
    altname enp23s0f0np0
3: ens81f1np1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr2 state UP group default qlen 1000
    link/ether a0:36:bc:cd:92:e8 brd ff:ff:ff:ff:ff:ff
    altname enp23s0f1np1
4: ens38f0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 50:7c:6f:70:2a:b4 brd ff:ff:ff:ff:ff:ff
    altname enp177s0f0
5: ens38f1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 50:7c:6f:70:2a:b5 brd ff:ff:ff:ff:ff:ff
    altname enp177s0f1
6: ens38f2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 50:7c:6f:70:2a:b6 brd ff:ff:ff:ff:ff:ff
    altname enp177s0f2
7: ens83f0np0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr1 state UP group default qlen 1000
    link/ether 40:a6:b7:c8:da:84 brd ff:ff:ff:ff:ff:ff
    altname enp24s0f0np0
8: ens38f3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 50:7c:6f:70:2a:b7 brd ff:ff:ff:ff:ff:ff
    altname enp177s0f3
9: ens83f1np1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr3 state UP group default qlen 1000
    link/ether 40:a6:b7:c8:da:85 brd ff:ff:ff:ff:ff:ff
    altname enp24s0f1np1
10: enx76c6b3d1c591: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 76:c6:b3:d1:c5:91 brd ff:ff:ff:ff:ff:ff
11: vmbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether a0:36:bc:cd:92:e7 brd ff:ff:ff:ff:ff:ff
    inet 10.16.0.4/21 scope global vmbr0
       valid_lft forever preferred_lft forever
    inet6 fe80::a236:bcff:fecd:92e7/64 scope link
       valid_lft forever preferred_lft forever
12: vmbr1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 40:a6:b7:c8:da:84 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.68/24 scope global vmbr1
       valid_lft forever preferred_lft forever
    inet6 fe80::42a6:b7ff:fec8:da84/64 scope link
       valid_lft forever preferred_lft forever
13: vmbr2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether a0:36:bc:cd:92:e8 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::a236:bcff:fecd:92e8/64 scope link
       valid_lft forever preferred_lft forever
1367: tap100i0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master fwbr100i0 state UNKNOWN group default qlen 1000
    link/ether fe:4e:12:17:bf:18 brd ff:ff:ff:ff:ff:ff
1371: tap100i1: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master fwbr100i1 state UNKNOWN group default qlen 1000
    link/ether 72:8e:5d:43:70:a4 brd ff:ff:ff:ff:ff:ff
1387: fwbr100i1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether a6:ea:5d:d5:5a:25 brd ff:ff:ff:ff:ff:ff
1388: fwpr100p1@fwln100i1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr2 state UP group default qlen 1000
    link/ether b6:f9:1c:42:2a:e9 brd ff:ff:ff:ff:ff:ff
1389: fwln100i1@fwpr100p1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master fwbr100i1 state UP group default qlen 1000
    link/ether a6:ea:5d:d5:5a:25 brd ff:ff:ff:ff:ff:ff
1393: vmbr3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 40:a6:b7:c8:da:85 brd ff:ff:ff:ff:ff:ff
    inet 10.16.0.5/21 scope global vmbr3
       valid_lft forever preferred_lft forever
    inet6 fe80::42a6:b7ff:fec8:da85/64 scope link
       valid_lft forever preferred_lft forever
1442: fwbr100i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether ea:ea:03:70:fa:56 brd ff:ff:ff:ff:ff:ff
1443: fwpr100p0@fwln100i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr3 state UP group default qlen 1000
    link/ether fe:10:1d:aa:12:cb brd ff:ff:ff:ff:ff:ff
1444: fwln100i0@fwpr100p0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master fwbr100i0 state UP group default qlen 1000
    link/ether ea:ea:03:70:fa:56 brd ff:ff:ff:ff:ff:ff
root@bcscallmgrproxmox:~# ip route
default via 10.16.0.1 dev vmbr3 proto kernel onlink
10.16.0.0/21 dev vmbr0 proto kernel scope link src 10.16.0.4
10.16.0.0/21 dev vmbr3 proto kernel scope link src 10.16.0.5
192.168.0.0/24 dev vmbr1 proto kernel scope link src 192.168.0.68
root@bcscallmgrproxmox:~# qm config 100 | grep net
boot: order=sata0;ide2;net0
net0: virtio=BC:24:11:B3:40:05,bridge=vmbr3,firewall=1
net1: virtio=BC:24:11:8A:0F:B5,bridge=vmbr2,firewall=1
root@bcscallmgrproxmox:~#

stakey · Friday at 20:47

Onslow said:
Welcome, stakey!
Hard to guess unless you post the full details of network settings of the host and of the VM .

From the host:

cat /etc/network/interfaces
ip a
ip route

qm config 100 | grep net
(assuming that the VM id is 100).

And the network settings from the VM.

In both situations: when it works and when it doesn't.

The commands and the outputs please post in the

Code:

tags (click < / > button in the upper menu).

I've posted them both to the thread. The first Post is using standard copper ethernet. The second (which doesn't work) is using the SFP+ port

Onslow · Friday at 21:02

From the sentence in the opening post
"I can ping it from my core it's connected to and load the management window perfectly fine"
I have understood you have been writing about the mgmt window of the VM.
But I still can't see the network settings from the VM.

Or are you writing about PVE mgmt window?
If yes, I suggest stopping the VM to avoid a possible impact of it on the network troubleshooting.

Onslow · Friday at 21:08

stakey said:
I've posted them both to the thread. The first Post is using standard copper ethernet. The second (which doesn't work) is using the SFP+ port

Somehow I can see only one post with the details...

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VM not passing traffic through SFP+ nic

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