With CSF active the port bandwidth drops drastically

[rogalde]

I have a VPS with Almalinux8, Cpanel and CSF installed and with a 600Mpbs port. I started experiencing speed issues with FTP uploads (because it limited data upload) and so to check the speeds from the server, I installed speedtest cli.

The results with CSF/LFD activated are:

Code: Select all

Idle Latency:     9.79 ms   (jitter: 6.93ms, low: 2.03ms, high: 24.56ms)
    Download:    50.82 Mbps (data used: 60.1 MB)
                363.07 ms   (jitter: 71.63ms, low: 40.45ms, high: 718.71ms)
      Upload:    69.13 Mbps (data used: 56.3 MB)
                275.46 ms   (jitter: 66.22ms, low: 6.46ms, high: 787.30ms)
 Packet Loss:     0.0%

The results with CSF/LFD disabled are:

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Idle Latency:     0.72 ms   (jitter: 0.74ms, low: 0.30ms, high: 1.62ms)
    Download:   558.68 Mbps (data used: 395.4 MB)
                  9.56 ms   (jitter: 3.18ms, low: 1.01ms, high: 87.33ms)
      Upload:   570.64 Mbps (data used: 256.8 MB)
                107.27 ms   (jitter: 33.75ms, low: 2.26ms, high: 249.56ms)
 Packet Loss:     0.0%

I have tried reinstalling CSF and at first it works perfectly but after 1 or 2 minutes it limits the port again.
I have also tried several profiles, the one that comes by default, low or high security, but nothing works.
The truth is that I don't know what to do to solve this. Could someone help me?

Thanks in advance.

[rogalde]

Hello again.
Unfortunately I have installed Almalinux8 as a new virtual machine in virtualbox on my Local PC and I notice that the same thing happens although with different speeds.

Is all this normal or is there some hidden setting that solves it?

Thanks

[rogalde]

After a few days of research I have only been able to solve the problem by cleaning IPTABLES and reinstalling the CSF with its tool in the "Fix Common Problems" section.

I have realized that the solution is not 100% permanent since after at least 15~20 days the port speed limitation problem has occurred again. I still don't know the correct cause but I do know that by deactivating the CSF everything returns to normal.

The solution is always to run these commands and reinstall the CSF.

From a terminal run as root:
1) csf -x (disable csf)
2) nft flush ruleset
3) iptables -F
4) Reinstall CSF from its "Fix Common Problems" section

I can't submit an official ticket because they are only for paid products and not this, but if some of the developers see this, it would be interesting if they could take a look.

Thanks.