Internet Speed Drops Drastically When Adding a Switch

Often we see a duplex mismatch as source of this problem.

If speed is fixed at UTM or provider-router ... you have to select a fix speed at the other end of the cable too.

Hi Mark PCF 

What do you see in the connection details in UTM and on your switch? Are there any hardware errors? You should take SSH of UTM and login as Root and then try ifconfig ethX it should give you some details about the interface issues. Check the Kernel logs as well.

I was hoping this was it singe the switch we put in was an unmanaged Gigabit and the UTM was set to 100Mbps/fullduplex.

Same problem remained when I replaced the Gigabit switch with a basic 10/100 though.

i think your unmanaged switches need "auto" settings at all ports.

Hi Mark and welcome to the UTM Community!

If Dirk's last suggestion doesn't fix things for you, experiment as suggested in #7.7 in Rulz (last updated 2019-04-17).

Cheers - Bob

Unfortunately, Dirk's suggestions did not work. The switch I am trying to use is a TP-Link TL-SG1016 gigabit switch and all ports are auto detecting (will connect at gigabit with a laptop). The UTM is set for 100 Mbps/full-duplex to match the NIC on the incomming fiber connection.

I still get the full 50/50Mbps up/down when directly connected, but anytime I put the switch between, the speed drops down to between 2-5Mbps. The switch indicates that the connection is using 100Mbps (The gigabit light is out on the 2 ports connected to the UTM and fiber equipment).

I will have to to the testing suggested early in the morning before most people get in to limit the network bottleneck while I am testing.

I will post what I find.

Good luck, but I bet you wind up getting a different switch.

Cheers - Bob

I bought a TPLINK firewall because it was cheap, and got what I paid for.   No support for the encryption options that are considered minimal-acceptable based on recent research.   Called their support to see if there was a better option, and got a nice lady with a Chinese accent would could not understand my version of English.

You will not have acceptable performance if a fixed link is matched to an auto-detect link, because the auto-detect side will activate half-duplex.   The duplex mode is not part of the auto-discover mechanism.

In your case, it sounds like you have a duplex problem on both ends - utm to switch and switch to ISP.    If you can get your ISP to switch to auto mode, you can make this work.

Good idea, thank you for the suggestion!

First i would try to configure the UTM with "auto" settings. This should match the switch settings.

If the problem is at the fiber-side ... you need another switch.

Or ask your ISP to configure the fibre-switch with "Auto"-settings too.

Sometimes this is possible.