Fixing high internal network latency on Mac OS

Over the last few months, I have been experiencing some strange issues on my work Mac OS (I use Windows as my daily driver at home, combined with OpenSuSE Tumbleweed).
While my WiFi worked perfectly on every other device at home, I was having serious issues on my Macbook. It had high internal latency in my network, which led me at first to issues with my ISP - however, this seemed not to be the case.

What symptoms did I have?

I use my Macbook at work exclusively using WiFi and it worked great there - never any issues or any problem with it. However, at home, I had a high latency between my internal network, with huge latency spikes between them.

I use Synergy to share my keyboard/mouse between my work laptop and my main desktop, so I don’t need to use another keyboard or replug them all of the time.
Synergy was having lag issues with very noticeable moments that the mouse and keyboard just stopped working on the Mac or with a huge delay.
My softphone was losing connection a lot during calls, which made taking telephone calls really hard.

I tried to debug things and this is the result of a ping between my Macbook and my desktop, on the same network (Macbook on WiFi, desktop wired):

64 bytes from 192.168.0.230: icmp_seq=21032 ttl=128 time=1469.006 ms
64 bytes from 192.168.0.230: icmp_seq=21033 ttl=128 time=465.320 ms
64 bytes from 192.168.0.230: icmp_seq=21034 ttl=128 time=205.240 ms
64 bytes from 192.168.0.230: icmp_seq=21035 ttl=128 time=91.271 ms
64 bytes from 192.168.0.230: icmp_seq=21036 ttl=128 time=124.840 ms
64 bytes from 192.168.0.230: icmp_seq=21037 ttl=128 time=7.685 ms
64 bytes from 192.168.0.230: icmp_seq=21038 ttl=128 time=2.090 ms
64 bytes from 192.168.0.230: icmp_seq=21039 ttl=128 time=2.003 ms
64 bytes from 192.168.0.230: icmp_seq=21040 ttl=128 time=1.968 ms
64 bytes from 192.168.0.230: icmp_seq=21041 ttl=128 time=2.868 ms
64 bytes from 192.168.0.230: icmp_seq=21042 ttl=128 time=6.469 ms
64 bytes from 192.168.0.230: icmp_seq=21043 ttl=128 time=23.722 ms
64 bytes from 192.168.0.230: icmp_seq=21044 ttl=128 time=2.454 ms
64 bytes from 192.168.0.230: icmp_seq=21045 ttl=128 time=1.963 ms
64 bytes from 192.168.0.230: icmp_seq=21046 ttl=128 time=1.945 ms
64 bytes from 192.168.0.230: icmp_seq=21047 ttl=128 time=559.158 ms
64 bytes from 192.168.0.230: icmp_seq=21048 ttl=128 time=897.496 ms
64 bytes from 192.168.0.230: icmp_seq=21049 ttl=128 time=1518.262 ms
64 bytes from 192.168.0.230: icmp_seq=21050 ttl=128 time=514.783 ms
64 bytes from 192.168.0.230: icmp_seq=21051 ttl=128 time=2.037 ms
64 bytes from 192.168.0.230: icmp_seq=21052 ttl=128 time=11.051 ms

These values are absolutely absurd for a local network - so I first blamed my router. However, pinging my smartphone from my desktop didn’t register this same latency.

In fact, it only exists when the Macbook is involved and that is what led me to investigate further.

The solution

The solution really baffled me, since I wouldn’t really link it together with this issue.

In order to solve this, I had to disable my location services. (System Preferences –> Security & Privacy –> Location Services –> Unlock –> Uncheck Enable Location Services).

Once this was disabled, all of my issues disappeared - I had normal network latency and both Synergy (which I use to share my keyboard between Mac/Windows), as well as my softphone, started working without any issues!

So I hope this can help you!

  • Kevin

(Image credit: https://pxhere.com//en/photo/851773)

Posted on Friday, 8 November 2019