pfSense is slowing down my internet

  • Hey all,

    I have Netgate SG-3100 connected to Xfinity rented modem with gigabit internet package. Before that I owned the modem and thought speed issue were due to bad modem.
    When connected directly to the modem using desktop computer I get full speed:


    When I connect pfSense to it my download speed is cut in half:


    I've tried toggling Disable hardware checksum offload and rebooted
    as suggested here but no joy.

    Can someone please share their experience how they fixed this issue?

    Here's the list of installed packages:


    Output of speedtest-cli

    [2.4.5-RELEASE][]/root: speedtest-cli
    Retrieving configuration...
    Testing from Comcast Cable (
    Retrieving server list...
    Selecting best server based on ping...
    Hosted by (Seattle, WA) [32.11 km]: 30.4 ms
    Testing download speed................................................................................
    Download: 434.61 Mbit/s
    Testing upload speed................................................................................................
    Upload: 25.91 Mbit/s

  • comcast modem in bridged mode?

  • @beachbum2021 said in pfSense is slowing down my internet:

    comcast modem in bridged mode?


  • i had a similar issue and found it to be ntop. Even then, on a 1gb comcast line I only get 700ish down hardwired. If i direct connect I get 950down. I also have a 3100. I'm not entirely sure why the netgate device does this either. When I was running ntop I saw pretty much the same speed as you. try resetting the modem and netgate again. I use a SB8200 modem.

  • if it makes you feel any better..1GB line-in and I get those speed (950 down)with the 3100 out of the equation. That said, I'm not sure I entirely understand where the issue lies if the 3100 can process more than 1GB throughput.
    1st test
    2nd test

  • Your issue is the traffic “inspection” packages installed:


    These packages put the Network Interface in Promiscious mode to get “copies”/access to frames sent and delivered on the interface. Promiscious mode requires copious amounts of CPU time to deliver and process frames within the software packages - something the ARM based appliances does not have. So effectively it kills throughput on your SG-3100. On 3100 it takes about half of the Gigabit throughput (just like what you are seeing). On the smaller SG-1100 and SG-2100 it takes slightly more than half (putting them @ about 200mbit).

    Uninstall those packages and your bandwidth will return to the promised 930ish mbit through pfSense.
    If you need those packages running, you have to get a bigger appliance - and so far an Intel based one. They can handle that load.

  • Thank you all for the replies!

    I removed all packages and left only:

    Did reboot and tested again. Still no joy. I was getting same speeds.
    I had Shuttle DS437 with:
    Intel Celeron CPU 1037U @ 1.80GHz
    Samsung 256GB SSD
    8GB of RAM.
    Installed fresh copy of pfSense and was getting same speeds.
    I was so frustrated that I downloaded Untangle and installed it on the Shuttle and I'm getting 900Mbps+ now.

    I'm using pfSense over 10+ years but with this I have to think about selling SG-3100 because even if I bought SG-5100 my speeds would not be above 900.

    If anyone has more ideas what to try I would be more than happy because I would love to continue to support pfSense!

  • See also :

    A test on reddit - see also the video - from 2018 shows 900+ over WAN.
    That is, the other ipferf3 side was on the WAN network, so the traffic was going through pfSense, version 2.4.3.

  • i've tested again, here are my stats. 1GB down @ Comcrap. I'm happy with this throughput considering suricata/extensive pfblocker lists.


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