# TCP Tuning Help



## jmcguire525 (Mar 25, 2018)

I'm having an issue where TCP streams from my Freenas server aren't able to utilize my 200Mb WAN bandwidth. I have a fiber PPPoE connection to a Ubiquiti USG Pro > Unifi Switch 16.

If I run iperf on my macbook with a 550k window size I can easily get 100Mbps from a single stream. If I run Plex on that macbook with media from an SMB share on my Freenas server I can remotely direct stream 4k (50Mbps) movies without issue.
With autotune on the Freenas server iperf jumps to ~90Mbps for the first 5-10 seconds and then comes down to ~30Mbps and stays there. 4k Streams from my Plex jail constantly buffer since they are limited to the same ~30Mbps.

I've played around with some of the TCP tunables, increasing the buffer size and such without any luck. One thing that is odd is Plex is able to play 4k fine through an indirect (relay) connection. Relay connections are supposed to be limited to 2Mbps but for some reason are able to Direct Stream to my remote Shield Tv. I'm not sure if that relay connection somehow differs from a normal TCP stream but something is allowing it to bypass whatever is wrong in my network tuning.

Any help would be greatly appreciated!


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## leebrown66 (Mar 25, 2018)

Please see Thread pc-bsd-freenas-nas4free-and-all-other-freebsd-derivatives.7290


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