Slow connections in a single direction

[adambarclay]

Hi,

Have been using pfSense for a while and have it setup and working pretty well, except for one odd issue related to bandwidth / transfer rate between various hosts.

I run pfSense 2.3.2-RELEASE-p1 on top of ESXi v6.0.0 Update 2 in a ProLiant Gen8 server. E31260L @ 2.40GHz CPU and 8GB memory, running from an SSD.

I have 3 interfaces (plus VPN not currently being used). DMZ, LAN & WAN.

Between various hosts on the network the speeds are only high in one direction (for example laptop -> mediaserver is quick, mediaserver -> laptop is slow). I have ran iperf3 tests to get these numbers (screenshot attached showing various routes and their throughput). But as an example:

laptop (LAN) -> mediaserver (DMZ): 46 Mbytes transfer, 39 Mbits/sec
mediaserver (DMZ) -> laptop (LAN): 2 Mbytes transfer, 2 Mbits/sec, 290 Retr, 5.66 Kbytes Cwnd

I thought the issue may have been just DMZ -> LAN but in one test LAN -> DMZ was slow for two hosts that live on the same box as the router (they all do, except for the laptop which goes through a Unifi-AC-Pro AP)

I've searched the forum and web to no avail, most results relate to IpSec / VPN usage being slow, not local-only problems.

Where could I start to look for potential issues?