Slow Internet but LAN is OK

M

marsara

New Member
May 16, 2025
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So I currently have a 1000/40 cable connection and I'm able to get full speed on all of my machines except for Proxmox (Host) and by extension all of the VMs, where I'm only able to get about 80-110mbps. LAN speeds however are unaffected, and I can get a full 1000/1000. Infact internet speeds always seem to be about 10% of the internet speed of any other device at a given instant.

Code: 
Connecting to host router, port 5201
[  5] local xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx port 33762 connected to xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx port 5201
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec   113 MBytes   945 Mbits/sec    0    439 KBytes
[  5]   1.00-2.00   sec   110 MBytes   921 Mbits/sec    0    478 KBytes
[  5]   2.00-3.00   sec   111 MBytes   929 Mbits/sec    0    478 KBytes
[  5]   3.00-4.00   sec   111 MBytes   927 Mbits/sec    0    554 KBytes
[  5]   4.00-5.00   sec   111 MBytes   929 Mbits/sec    0    554 KBytes
[  5]   5.00-6.00   sec   111 MBytes   934 Mbits/sec    0    554 KBytes
[  5]   6.00-7.00   sec   111 MBytes   928 Mbits/sec    0    554 KBytes
[  5]   7.00-8.00   sec   109 MBytes   911 Mbits/sec    0    580 KBytes
[  5]   8.00-9.00   sec   106 MBytes   893 Mbits/sec    0    580 KBytes
[  5]   9.00-10.00  sec   108 MBytes   909 Mbits/sec    0    580 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  1.07 GBytes   923 Mbits/sec    0             sender
[  5]   0.00-10.00  sec  1.07 GBytes   920 Mbits/sec                  receiver

iperf Done.

Code: 
Retrieving speedtest.net configuration...
Testing from Spectrum (xx.xx.xx.xx)...
Retrieving speedtest.net server list...
Retrieving information for the selected server...
Hosted by ****: 27.858 ms
Testing download speed................................................................................
Download: 63.72 Mbit/s
Testing upload speed......................................................................................................
Upload: 18.14 Mbit/s

Code: 
Retrieving speedtest.net configuration...
Testing from Spectrum (xx.xx.xx.xx)...
Retrieving speedtest.net server list...
Selecting best server based on ping...
Hosted by ****: 20.979 ms
Testing download speed................................................................................
Download: 692.32 Mbit/s
Testing upload speed......................................................................................................
Upload: 27.71 Mbit/s

Code: 
00:00.0 Host bridge: Intel Corporation Device 7d14 (rev 04)
00:02.0 VGA compatible controller: Intel Corporation Meteor Lake-P [Intel Arc Graphics] (rev 08)
00:04.0 Signal processing controller: Intel Corporation Meteor Lake-P Dynamic Tuning Technology (rev 04)
00:06.0 PCI bridge: Intel Corporation Device 7e4d (rev 20)
00:08.0 System peripheral: Intel Corporation Meteor Lake-P Gaussian & Neural-Network Accelerator (rev 20)
00:0a.0 Signal processing controller: Intel Corporation Meteor Lake-P Platform Monitoring Technology (rev 01)
00:0b.0 Processing accelerators: Intel Corporation Meteor Lake NPU (rev 04)
00:0d.0 USB controller: Intel Corporation Meteor Lake-P Thunderbolt 4 USB Controller (rev 10)
00:0e.0 RAID bus controller: Intel Corporation Volume Management Device NVMe RAID Controller Intel Corporation
00:14.0 USB controller: Intel Corporation Meteor Lake-P USB 3.2 Gen 2x1 xHCI Host Controller (rev 20)
00:14.2 RAM memory: Intel Corporation Device 7e7f (rev 20)
00:16.0 Communication controller: Intel Corporation Meteor Lake-P CSME HECI (rev 20)
00:17.0 SATA controller: Intel Corporation Device 7e63 (rev 20)
00:1c.0 PCI bridge: Intel Corporation Device 7e3c (rev 20)
00:1c.5 PCI bridge: Intel Corporation Device 7e3d (rev 20)
00:1c.7 PCI bridge: Intel Corporation Device 7e3f (rev 20)
00:1f.0 ISA bridge: Intel Corporation Device 7e02 (rev 20)
00:1f.3 Audio device: Intel Corporation Meteor Lake-P HD Audio Controller (rev 20)
00:1f.4 SMBus: Intel Corporation Meteor Lake-P SMBus Controller (rev 20)
00:1f.5 Serial bus controller: Intel Corporation Meteor Lake-P SPI Controller (rev 20)
01:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd NVMe SSD Controller PM9C1a (DRAM-less)
02:00.0 Ethernet controller: Intel Corporation Ethernet Controller I226-V (rev 06)
03:00.0 Ethernet controller: Intel Corporation Ethernet Controller I226-V (rev 06)
04:00.0 Network controller: Intel Corporation Wi-Fi 7(802.11be) AX1775*/AX1790*/BE20*/BE401/BE1750* 2x2 (rev 1a)

Code: 
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 002: ID 10c4:ea60 Silicon Labs CP210x UART Bridge
Bus 003 Device 003: ID 8087:0036 Intel Corp.
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 002: ID 0bda:8153 Realtek Semiconductor Corp. RTL8153 Gigabit Ethernet Adapter
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Code: 
auto lo
iface lo inet loopback

iface enp2s0 inet manual # 2.5G intel onboard
iface enp3s0 inet dhcp #2.5G intel onboard

auto enxd8ec5eb6dfde
iface enxd8ec5eb6dfde inet dhcp # 1G realtek usb adapter

auto vmbr0
iface vmbr0 inet dhcp # IP is reserved at the router
        bridge-ports enp2s0
        bridge-stp off
        bridge-fd 0

iface wlp4s0f0 inet manual

Code: 
Settings for enp2s0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
                                2500baseT/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
                                2500baseT/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: 0
        Transceiver: internal
        MDI-X: off (auto)
        Supports Wake-on: pumbg
        Wake-on: g
        Current message level: 0x00000007 (7)
                               drv probe link
        Link detected: yes

You can find more on the machine that this is running on here: https://shop.asus.com/us/asus-expertcenter-pn65.html

I've only copied the output for a single test on each, but the results are the same regardless of which interface I bind either iperf or speedtest to.
I've also tried using different interfaces, including an external USB-C -> gigabit adapter as you can see from my interfaces file. I've also tried creating a bond between the two 2.5G adapters but that caused issues with all of the VMs losing their ipv4 DHCP address but that's a separate issue that I'll worry about later.

If anyone sees anything obvious from the output above or has any ideas... But my next plan is to try and boot up a live USB, in a few days, with Ubuntu on it and see if I see the same performance there; to try and rule out hardware issues. But as I've already tried a USB adapter, I'm not very hopeful. I also have a backup mini-pc that I might try installing Proxmox on and configure it similarly to what I have here and see if it also experiences the same issue.
 
So when you troubleshot with the Realtek you set it to inet manual and added it to vmbr0 ? then unplugged the intels?

I don't know anything about these 2.5 intels except people seem to complain about them. there's a new kernel avail...
t.lamprecht

Thread 'Opt-in Linux 6.14 Kernel for Proxmox VE 8 available on test & no-subscription'

We recently uploaded a 6.14 kernel into our repositories. The current 6.8 kernel will stay the default on the Proxmox VE 8 series, the newly introduced 6.14 kernel is an option.
The 6.14 based kernel may be useful for some (especially newer) setups, for example if there is improved hardware support that has not yet been backported to 6.8.
This follows our tradition of upgrading the Proxmox VE kernel to match the current Ubuntu version until we reach an (Ubuntu) LTS release, like the 6.8 kernel is, and then provide newer kernels as opt-in. The 6.14 kernel is based on the Ubuntu 25.04 Plucky...
  • Like
maybe opt-in and roll the dice on it(?)
 
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Going to try the realtek again but I would just enable it and then run
Code: 
speedtest-cli --source <IP address>

But I'm starting to think that it's definitely the i226-v's. I installed proxmox on another mini computer and was able to get 700-900mbps. I then booted up an Ubuntu live USB on this mini and even there I only saw 60-90mbps.

Something else that I thought was odd though. If I ran iperf3 from proxmox -> router I would still see 900+ mbps. But if I ran it from router -> proxmox I'd only get 100-200mbps initially.

Definitely going to try again with the Realtek and see if maybe my initial tests were just incorrect.
 
the nice thing about putting the realtek on the bridge is that the promox IP stays the same and you can just move the cable around to test. works with the VMs too.

you could run bidir or dualtest with iperf3 to be more confident there's a prob receiving
 
Ya, redid my test with the Realtek and now I'm seeing ~900mbps. While this isn't ideal as I was preferring the dual NIC so I eventually could setup a bond. But looks like it's the i226-v causing the problem.

p.s. for anyone else running into this it looks like this is the same issue: https://forum.opnsense.org/index.php?topic=18754.150

Currently in the process to RMA the PC to ASUS and see what they discover.
 
linux 6.15 kernel has many intel driver updates and igc is included. the opt-in is 6.14 but you could probably find an ubuntu 6.15 and try it out.
RMAs like this take forever unless they have a known prob and just swap you out.

nevermind, the 6.15 handles a prob re: link down events with igc that you'd be seeing in system log.
 
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