vmbr0 causing drops

[ben29]

Hi.
so i installed proxmox 8.1 on Vultr bare metal

when i use the default settings of proxmox like that:

iface enp1s0f0 inet manual

auto vmbr0
iface vmbr0 inet static
    address x.x.x.x/23
    gateway x.x.x.x
    bridge-ports enp1s0f0
    bridge-stp off
    bridge-fd 0

i have a lot of RX drops!

when i change to work without the bridge

auto enp1s0f0
iface enp1s0f0 inet static
    address x.x.x.x
    gateway x.x.x.x

no drops at all!!
i don't understand why it's happen!

thanks!

 

[sb-jw]

address x.x.x.x/23

Are you sure you have a /23 network?

i have a lot of RX drops!

How do you check that? Can you post the excerpt here.

 

[ben29]

Are you sure you have a /23 network?


How do you check that? Can you post the excerpt here.

1. yes. it's the Vultr server public ip.
2. i just did ifconfig and see....

 

[sb-jw]

Does this actually affect your traffic? Maybe it's just a bunch of junk coming to your server. A /23 is a larger broadcast domain and when they are all occupied and everyone fires an ARP request.

You can simply check what's going on via tcpdump.

 

[ben29]

Does this actually affect your traffic? Maybe it's just a bunch of junk coming to your server. A /23 is a larger broadcast domain and when they are all occupied and everyone fires an ARP request.

You can simply check what's going on via tcpdump.

i only see when i do. tcpdump, kernel drop the packages...

 

[sb-jw]

kernel drop the package

packets ‘‘dropped by kernel’’(this is the number of packets that were dropped,due to a lack of buffer space,by the packet capture mechanism in the OS on which tcpdump is running,if the OS reports that information to applications; if not, it will be reported as 0).

Source: https://man7.org/linux/man-pages/man1/tcpdump.1.html

 

[ben29]

Source: https://man7.org/linux/man-pages/man1/tcpdump.1.html

when i run tcpdump for few seconds i get "21 packages droped by kernel "

but when i use tcpdump -w report few minutes.
no dropped packages... even using -B 4096 or 8192....

weird...

 

[spirit]

can you try

iface enp1s0f0 inet manual

auto vmbr0
iface vmbr0 inet static
    address x.x.x.x/23
    gateway x.x.x.x
    bridge-ports enp1s0f0
    bridge-stp off
    bridge-fd 0
    bridge-disable-mac-learning 1
    bridge-vlan-aware yes
    bridge-vids 2-4096

by default, enp1s0f0 is in promisc mode if enslave in a bridge. (Maybe Vultr is sending you bad traffic not destinated to your ip, We have see this with Hetzner for example).

bridge-disable-mac-learning 1 should avoid to forward bad traffic to vm, and bridge-vlan-aware need to be enabled (even if you don't use any vlan). enp1s0f0 should disable prosmisc mode with this config.