Slow Network (Newbie learning)

Heretolearn

New Member
Jun 12, 2025
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Hello Community
Thank you for reading my post
Full disclosure, I am brand new to the world of Proxmox, so my apologies if I have provided the wrong info
I set up my new test environment with the help of the documentation, forms and Google. I managed to get quite far, but this issue is beyond my knowledge of Google skills
I am guessing I have misconfigured something :-(

The issue
I am only getting around 6/8 Mbps from my VMS (used Speed test)
Possibly something to do with Cwnd (see below)

My Environment
A single node - old Dell Tower Server

Network

I have the following network cards
/W path Device Class Description
=========================================================
/0/100/1/0/0 enp2s0 network NetXtreme II BCM5708 Gigabit Ethernet
/0/100/1.1/0/2/0 enp5s0f0 network 82576 Gigabit Network Connection
/0/100/1.1/0/2/0.1 enp5s0f1 network 82576 Gigabit Network Connection
/0/100/1.1/0/4/0 enp6s0f0 network 82576 Gigabit Network Connection
/0/100/1.1/0/4/0.1 enp6s0f1 network 82576 Gigabit Network Connection
/0/100/1c.4/0 eno1 network NetXtreme BCM5722 Gigabit Ethernet PCI Express
/0/100/1c.5/0 network RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller

I am using the Ethernet controller: Intel Corporation 82576 Gigabit Network Connections 4 NICs on one card to handle the networking

I have added each port to a Bridge to allow me to contact the outside world

eno1 - Web console Management port
enp5s0f0 Internet
enp5s0f1 WAN
enp6s0f0 LAN
enp6s0f1 LAN2
I have ports 2-4 connected to a Pfense route, Port 1 is connected straight to my router, and I still have a poor download speed
I have a Windows DHCP server handling address and DNS on my segmented LANs

Network settings
Settings for enp5s0f1:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supported pause frame use: Symmetric
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised pause frame use: Symmetric
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
Speed: 1000Mb/s
Duplex: Full
Auto-negotiation: on
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
MDI-X: off (auto)
Supports Wake-on: d
Wake-on: d
Current message level: 0x00000007 (7)
drv probe link
Link detected: yes

Network config file
auto lo
iface lo inet loopback

iface enp2s0 inet manual

iface eno1 inet manual

iface enp9s0 inet manual

iface enp5s0f0 inet manual

iface enp5s0f1 inet manual

iface enp6s0f0 inet manual

iface enp6s0f1 inet manual

auto vmbr0
iface vmbr0 inet dhcp
bridge-ports enp2s0
bridge-stp off
bridge-fd 0


root@Prox01:~# ip add
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: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr0 state UP group default qlen 1000
link/ether 00:10:18:39:9b:52 brd ff:ff:ff:ff:ff:ff
3: eno1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether d4:ae:52:c8:e8:8f brd ff:ff:ff:ff:ff:ff
altname enp8s0
4: enp5s0f0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq master vmbr4 state DOWN group default qlen 1000
link/ether 00:1b:21:72:f5:88 brd ff:ff:ff:ff:ff:ff
5: enp5s0f1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr3 state UP group default qlen 1000
link/ether 00:1b:21:72:f5:89 brd ff:ff:ff:ff:ff:ff
6: enp6s0f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr2 state UP group default qlen 1000
link/ether 00:1b:21:72:f5:8c brd ff:ff:ff:ff:ff:ff
7: enp6s0f1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr1 state UP group default qlen 1000
link/ether 00:1b:21:72:f5:8d brd ff:ff:ff:ff:ff:ff
8: vmbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 00:10:18:39:9b:52 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.115/24 brd 192.168.1.255 scope global vmbr0
valid_lft forever preferred_lft forever
inet6 fe80::210:18ff:fe39:9b52/64 scope link
valid_lft forever preferred_lft forever
9: vmbr1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 00:1b:21:72:f5:8d brd ff:ff:ff:ff:ff:ff
inet6 fe80::21b:21ff:fe72:f58d/64 scope link
valid_lft forever preferred_lft forever
10: vmbr2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 00:1b:21:72:f5:8c brd ff:ff:ff:ff:ff:ff
inet 10.0.0.1/25 scope global vmbr2
valid_lft forever preferred_lft forever
inet6 fe80::21b:21ff:fe72:f58c/64 scope link
valid_lft forever preferred_lft forever
11: vmbr3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 00:1b:21:72:f5:89 brd ff:ff:ff:ff:ff:ff
inet6 fe80::21b:21ff:fe72:f589/64 scope link
valid_lft forever preferred_lft forever
12: vmbr4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 00:1b:21:72:f5:88 brd ff:ff:ff:ff:ff:ff
inet 10.0.0.129/25 scope global vmbr4
valid_lft forever preferred_lft forever
inet6 fe80::21b:21ff:fe72:f588/64 scope link
valid_lft forever preferred_lft forever
13: tap101i0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master fwbr101i0 state UNKNOWN group default qlen 1000
link/ether ee:d5:54:74:a4:8a brd ff:ff:ff:ff:ff:ff
14: fwbr101i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether fe:74:ff:82:c7:18 brd ff:ff:ff:ff:ff:ff
15: fwpr101p0@fwln101i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr1 state UP group default qlen 1000
link/ether 7e:e1:f6:88:e6:4e brd ff:ff:ff:ff:ff:ff
16: fwln101i0@fwpr101p0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master fwbr101i0 state UP group default qlen 1000
link/ether fe:74:ff:82:c7:18 brd ff:ff:ff:ff:ff:ff
17: tap101i1: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master fwbr101i1 state UNKNOWN group default qlen 1000
link/ether 0a:b6:74:d9:09:00 brd ff:ff:ff:ff:ff:ff
18: fwbr101i1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 72:b0:bc:d4:6f:34 brd ff:ff:ff:ff:ff:ff
19: fwpr101p1@fwln101i1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr2 state UP group default qlen 1000
link/ether ba:b5:89:3d:71:d9 brd ff:ff:ff:ff:ff:ff
20: fwln101i1@fwpr101p1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master fwbr101i1 state UP group default qlen 1000
link/ether 72:b0:bc:d4:6f:34 brd ff:ff:ff:ff:ff:ff
21: tap101i2: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master fwbr101i2 state UNKNOWN group default qlen 1000
link/ether be:74:32:2f:81:b3 brd ff:ff:ff:ff:ff:ff
22: fwbr101i2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 62:d6:e7:2c:e3:0d brd ff:ff:ff:ff:ff:ff
23: fwpr101p2@fwln101i2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr4 state UP group default qlen 1000
link/ether fa:d5:ae:dc:d8:ca brd ff:ff:ff:ff:ff:ff
24: fwln101i2@fwpr101p2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master fwbr101i2 state UP group default qlen 1000
link/ether 62:d6:e7:2c:e3:0d brd ff:ff:ff:ff:ff:ff
25: tap201i0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master fwbr201i0 state UNKNOWN group default qlen 1000
link/ether 26:ff:34:d4:71:78 brd ff:ff:ff:ff:ff:ff
26: fwbr201i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether f2:33:55:ec:64:ad brd ff:ff:ff:ff:ff:ff
27: fwpr201p0@fwln201i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr2 state UP group default qlen 1000
link/ether fe:89:29:f9:0c:e2 brd ff:ff:ff:ff:ff:ff
28: fwln201i0@fwpr201p0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master fwbr201i0 state UP group default qlen 1000
link/ether f2:33:55:ec:64:ad brd ff:ff:ff:ff:ff:ff
29: tap102i0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master fwbr102i0 state UNKNOWN group default qlen 1000
link/ether 12:cd:bc:af:89:bc brd ff:ff:ff:ff:ff:ff
30: fwbr102i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether ea:67:1c:ce:f4:ab brd ff:ff:ff:ff:ff:ff
31: fwpr102p0@fwln102i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr2 state UP group default qlen 1000
link/ether 6a:b3:63:e8:76:e6 brd ff:ff:ff:ff:ff:ff
32: fwln102i0@fwpr102p0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master fwbr102i0 state UP group default qlen 1000
link/ether ea:67:1c:ce:f4:ab brd ff:ff:ff:ff:ff:ff

from the research I have done this command should help

ID] Interval Transfer Bitrate Retr Cwnd
[ 5] 0.00-1.00 sec 3.71 GBytes 31.9 Gbits/sec 0 3.31 MBytes
[ 5] 1.00-2.00 sec 3.72 GBytes 32.0 Gbits/sec 0 3.31 MBytes
[ 5] 2.00-3.00 sec 3.74 GBytes 32.1 Gbits/sec 0 3.31 MBytes
[ 5] 3.00-4.00 sec 3.75 GBytes 32.2 Gbits/sec 0 3.43 MBytes
[ 5] 4.00-5.00 sec 3.73 GBytes 32.1 Gbits/sec 0 3.43 MBytes
[ 5] 5.00-6.00 sec 3.73 GBytes 32.1 Gbits/sec 0 3.93 MBytes
[ 5] 6.00-7.00 sec 3.73 GBytes 32.0 Gbits/sec 0 3.93 MBytes
[ 5] 7.00-8.00 sec 3.76 GBytes 32.3 Gbits/sec 0 3.93 MBytes
[ 5] 8.00-9.00 sec 3.76 GBytes 32.3 Gbits/sec 0 5.93 MBytes
[ 5] 9.00-10.00 sec 3.78 GBytes 32.4 Gbits/sec 0 5.93 MBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 37.4 GBytes 32.1 Gbits/sec 0 sender
[ 5] 0.00-10.00 sec 37.4 GBytes 32.1 Gbits/sec receiver


bios: ovmf
boot: order=scsi0;ide2;ide0
cores: 1
cpu: x86-64-v2-AES
ide0: Datastore1:iso/virtio-win-0.1.271.iso,media=cdrom,size=709474K
ide2: Datastore1:iso/Win11_24H2_English_x64.iso,media=cdrom,size=5683090K
machine: pc-i440fx-9.2+pve1
memory: 4096
meta: creation-qemu=9.2.0,ctime=1756754472
name: VM-Downloads
net0: virtio=BC:24:11:55:C7:FA,bridge=vmbr3,firewall=1
numa: 0
ostype: win11
scsi0: Data2:100/vm-100-disk-0.qcow2,iothread=1,size=120G
scsihw: virtio-scsi-single
smbios1: uuid=52f23396-7acb-4e2a-8878-cd73f0bc8056
sockets: 2
tags: Downloads
tpmstate0: Datastore1:100/vm-100-disk-0.raw,size=4M,version=v2.0
unused0: local-lvm:vm-100-disk-0
vmgenid: 2831def3-e125-42f5-9b0b-a702d998b2a6