[SOLVED] Not Working Bridge on Proxmox as VM

Ice Drake

New Member
Jul 5, 2021
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I am struggling for a few days trying to create three new working network bridges on Proxmox VE 5.3-6. I tried to reproduce the similar networking setting I made in the past. So far, I can't get any IP address to be assigned by my external DHCP server (or router) for any ethernet adapter on any of my LXCs and VMs whenever I setup the ethernet adapter to be connected to vmbr5 and vmbr6. But it works with no issue for my old vmbr2 and vmbr3.

/etc/network/interfaces
Code:
auto lo
iface lo inet loopback

iface eth0 inet manual

iface eth1 inet manual

iface eth2 inet manual

iface eth3 inet manual

iface eth4 inet manual

auto vmbr2
iface vmbr2 inet manual
    bridge_ports eth0
    bridge_stp off
    bridge_fd 0

auto vmbr3
iface vmbr3 inet dhcp
    bridge_ports eth1
    bridge_stp off
    bridge_fd 0

auto vmbr4
iface vmbr4 inet manual
    bridge_ports eth2
    bridge_stp off
    bridge_fd 0

auto vmbr5
iface vmbr5 inet manual
    bridge_ports eth3
    bridge_stp off
    bridge_fd 0

auto vmbr6
iface vmbr6 inet manual
    bridge_ports eth4
    bridge_stp off
    bridge_fd 0

ip link output:
Code:
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr2 state UP mode DEFAULT group default qlen 1000
    link/ether 00:15:5d:01:65:10 brd ff:ff:ff:ff:ff:ff
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr3 state UP mode DEFAULT group default qlen 1000
    link/ether 00:15:5d:01:65:11 brd ff:ff:ff:ff:ff:ff
4: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr4 state UP mode DEFAULT group default qlen 1000
    link/ether 00:15:5d:01:65:26 brd ff:ff:ff:ff:ff:ff
5: eth3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr5 state UP mode DEFAULT group default qlen 1000
    link/ether 00:15:5d:01:65:27 brd ff:ff:ff:ff:ff:ff
6: eth4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr6 state UP mode DEFAULT group default qlen 1000
    link/ether 00:15:5d:01:65:28 brd ff:ff:ff:ff:ff:ff
7: vmbr2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 00:15:5d:01:65:10 brd ff:ff:ff:ff:ff:ff
8: vmbr3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 00:15:5d:01:65:11 brd ff:ff:ff:ff:ff:ff
9: vmbr4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 00:15:5d:01:65:26 brd ff:ff:ff:ff:ff:ff
10: vmbr5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 00:15:5d:01:65:27 brd ff:ff:ff:ff:ff:ff
11: vmbr6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 00:15:5d:01:65:28 brd ff:ff:ff:ff:ff:ff
13: veth100i0@if12: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr2 state UP mode DEFAULT group default qlen 1000
    link/ether fe:14:49:00:19:9a brd ff:ff:ff:ff:ff:ff link-netnsid 0
15: veth101i0@if14: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr5 state UP mode DEFAULT group default qlen 1000
    link/ether fe:bc:26:c5:a0:f4 brd ff:ff:ff:ff:ff:ff link-netnsid 1
16: tap202i0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr2 state UNKNOWN mode DEFAULT group default qlen 1000
    link/ether fa:9f:ad:7a:27:1f brd ff:ff:ff:ff:ff:ff
17: tap202i1: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr3 state UNKNOWN mode DEFAULT group default qlen 1000
    link/ether 26:3c:93:d9:9e:cc brd ff:ff:ff:ff:ff:ff
18: tap202i2: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr4 state UNKNOWN mode DEFAULT group default qlen 1000
    link/ether ce:36:17:74:f1:65 brd ff:ff:ff:ff:ff:ff
19: tap202i3: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr6 state UNKNOWN mode DEFAULT group default qlen 1000
    link/ether 82:6f:0f:f0:db:09 brd ff:ff:ff:ff:ff:ff
21: veth102i0@if20: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr3 state UP mode DEFAULT group default qlen 1000
    link/ether fe:e2:9b:8f:fe:73 brd ff:ff:ff:ff:ff:ff link-netnsid 2
23: veth103i0@if22: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr3 state UP mode DEFAULT group default qlen 1000
    link/ether fe:c8:d3:cc:42:c9 brd ff:ff:ff:ff:ff:ff link-netnsid 3
25: veth105i0@if24: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr3 state UP mode DEFAULT group default qlen 1000
    link/ether fe:e1:14:ec:ca:d5 brd ff:ff:ff:ff:ff:ff link-netnsid 4
26: tap200i0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr2 state UNKNOWN mode DEFAULT group default qlen 1000
    link/ether ce:00:6b:3b:bd:12 brd ff:ff:ff:ff:ff:ff
27: tap200i1: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr5 state UNKNOWN mode DEFAULT group default qlen 1000
    link/ether 52:2b:7e:b7:85:ca brd ff:ff:ff:ff:ff:ff
28: tap200i2: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr6 state UNKNOWN mode DEFAULT group default qlen 1000
    link/ether 42:f4:89:5b:28:9a brd ff:ff:ff:ff:ff:ff

ip addr output:
Code:
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
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr2 state UP group default qlen 1000
    link/ether 00:15:5d:01:65:10 brd ff:ff:ff:ff:ff:ff
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr3 state UP group default qlen 1000
    link/ether 00:15:5d:01:65:11 brd ff:ff:ff:ff:ff:ff
4: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr4 state UP group default qlen 1000
    link/ether 00:15:5d:01:65:26 brd ff:ff:ff:ff:ff:ff
5: eth3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr5 state UP group default qlen 1000
    link/ether 00:15:5d:01:65:27 brd ff:ff:ff:ff:ff:ff
6: eth4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr6 state UP group default qlen 1000
    link/ether 00:15:5d:01:65:28 brd ff:ff:ff:ff:ff:ff
7: vmbr2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:15:5d:01:65:10 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::215:5dff:fe01:6510/64 scope link
       valid_lft forever preferred_lft forever
8: vmbr3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:15:5d:01:65:11 brd ff:ff:ff:ff:ff:ff
    inet 192.168.3.4/24 brd 192.168.3.255 scope global vmbr3
       valid_lft forever preferred_lft forever
    inet6 fe80::215:5dff:fe01:6511/64 scope link
       valid_lft forever preferred_lft forever
9: vmbr4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:15:5d:01:65:26 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::215:5dff:fe01:6526/64 scope link
       valid_lft forever preferred_lft forever
10: vmbr5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:15:5d:01:65:27 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::215:5dff:fe01:6527/64 scope link
       valid_lft forever preferred_lft forever
11: vmbr6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:15:5d:01:65:28 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::215:5dff:fe01:6528/64 scope link
       valid_lft forever preferred_lft forever
13: veth100i0@if12: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr2 state UP group default qlen 1000
    link/ether fe:14:49:00:19:9a brd ff:ff:ff:ff:ff:ff link-netnsid 0
15: veth101i0@if14: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr5 state UP group default qlen 1000
    link/ether fe:bc:26:c5:a0:f4 brd ff:ff:ff:ff:ff:ff link-netnsid 1
16: tap202i0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr2 state UNKNOWN group default qlen 1000
    link/ether fa:9f:ad:7a:27:1f brd ff:ff:ff:ff:ff:ff
17: tap202i1: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr3 state UNKNOWN group default qlen 1000
    link/ether 26:3c:93:d9:9e:cc brd ff:ff:ff:ff:ff:ff
18: tap202i2: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr4 state UNKNOWN group default qlen 1000
    link/ether ce:36:17:74:f1:65 brd ff:ff:ff:ff:ff:ff
19: tap202i3: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr6 state UNKNOWN group default qlen 1000
    link/ether 82:6f:0f:f0:db:09 brd ff:ff:ff:ff:ff:ff
21: veth102i0@if20: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr3 state UP group default qlen 1000
    link/ether fe:e2:9b:8f:fe:73 brd ff:ff:ff:ff:ff:ff link-netnsid 2
23: veth103i0@if22: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr3 state UP group default qlen 1000
    link/ether fe:c8:d3:cc:42:c9 brd ff:ff:ff:ff:ff:ff link-netnsid 3
25: veth105i0@if24: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr3 state UP group default qlen 1000
    link/ether fe:e1:14:ec:ca:d5 brd ff:ff:ff:ff:ff:ff link-netnsid 4
26: tap200i0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr2 state UNKNOWN group default qlen 1000
    link/ether ce:00:6b:3b:bd:12 brd ff:ff:ff:ff:ff:ff
27: tap200i1: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr5 state UNKNOWN group default qlen 1000
    link/ether 52:2b:7e:b7:85:ca brd ff:ff:ff:ff:ff:ff
28: tap200i2: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr6 state UNKNOWN group default qlen 1000

Since Proxmox VE runs on another host as a VM and I added three more ethernet ports to the VM, the only thing that I think I might be doing wrong is maybe Proxmox didn't connect the three new devices to the three new ethernet adapters? But I don't know how I can check that.
 
Last edited:

Ice Drake

New Member
Jul 5, 2021
5
0
1
39
I finally find the problem. The network configuration is correct, but I need to enable MAC address spoofing on the VM host for the network adapter.
 

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