Slow LAN speeds but Correct WAN speed?

  • Hello pfSense Community!

    This is my first post and first time using pfSense so please bear with me :)

    I recently installed pfSense community edition on a beefy Dell R210 ii with a quad-port Intel I-350 NIC. I have basically gone with default settings on the install. I learned I could check the connection speeds on the pfSense box itself using the speedtest CLI.

    I typically get 500 MB/s down and up from my ISP, and when I run 'speedtest-cli' on the pfSense box itself i surely get around those speeds: 512 MB/s down and 470 MB/s up.

    I have gotten similar tests on my laptop before when direct connected to my WAN, and when connected wired to my previous consumer wireless router as well. However, running a or test with the same laptop, hardwired the same way, except this time to the LAN port of the pfSense box: I only get about 280-300 MB/s down and ~270 MB/s up.

    I am almost pulling my hair out trying to figure what is causing this slow down on the LAN side. Are there any settings that I should be looking?

    I can confirm this similar slower speed on other devices when connected wired to the LAN port on the pfSense. It seems like something on the pfSense is causing my speeds to be much lower than my WAN speed..

    I would greatly appreciate help in helping me resolve this! Thanks in advance! :)

  • Netgate Administrator

    Those speeds look to high to be a link negotiation issue on LAN. You should check Status > Interfaces anyway though. Check for errors or collisions on LAN.

    Try re-assigning LAN to a different port. Try swapping out cables.


  • Hi @stephenw10, I posted on Reddit with more details. ( )

    . I originally had bridged 3 'OPT' ports as a LAN interface ( ) to set up some components on my homelab. I had preformed some speedtests before doing this, connected directly to the default single LAN port on the pfSense box, and am pretty sure that I was experiencing the slow speeds. So after bridging, I tested again, and didn't think much of it. It seemed to preform the same.

    I posted a screenshot of my pfsense dashboard when my ports were bridged. I noticed that under 'Interface Statistics' there appear to be a number of 'Errors Out' on LAN, and I am not sure what that meant?

    I have since preformed a factory reset, no bridging ports this time, and I am getting the ~500 Mb/s up/down from my ISP on the WAN and LAN side, even when testing when connecting my laptop to the UniFi switch (one additional hardware between WAN) virtually the same speed +/- only a few Mb/s!

    I am not sure that bridging was the blame, because as I mentioned, I recall seeing the similarly slower speed on the LAN side before doing so. However, can bridging ports to create a bridged LAN interface cause this big of a drop?

    I've also read about 'Hardware TCP Segmentation Offloading' and 'Hardware Large Receive Offloading' and how they can sometimes affect speeds. These are selected by default and I hadn't moved them before, or now, but I am wondering if these default settings can somehow be to blame?

  • Netgate Administrator

    Those offloading options should be disabled by default (checked). It rarely improves performance and can cause massive problems so I would not recommend enabling them. You might also disable Hardware Checksum Offloading as that can cause problems on some NICs.
    I would not normally expect bridging to cause a throughput issue on a system like that but if you were seeing output errors it was clearly hitting some issue. Unless you had a wifi interface in the mix there for example.


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