Dropped Network Connections

WiFi is so much fun, because everything is NOT under your control.

First I would see if you can use Ethernet (at least as an experiment). This would isolate the issue to WiFi and not some other networking issue.

WiFi interference can come from

• poorly shielded USB3 devices. This can be the device, the cable (especially if a USB2 cable is used instead of a USB3 cable), and even the connector, which could be a Thunderbolt connector because USB3 signals are passed through Thunderbolt (there have been reported cases of bad Thunderbolt connectors).
• Weak signals because the distance between the WiFi access point and the Mac is far enough or has enough WiFi blocking objects in the middle (metal, water, reenforced concrete, metal studs in the walls,water heaters, refridgerator, etc...), that any interference will disrupt the connection.
• A Microwave oven is near the WiFi access point or the Mac, or in the middle. Microwaves operate in the 2.4GHz frequencies. 2.4GHz was given over to WiFi because water blocks the signal, and long distance communications always runs into humidity, rain, snow, etc... that messes up 2.4GHz
• Cordless phones using the 2.4GHz signals (could be you, or your neighbors)
• Cordless baby monitors using the 2.4GHz signals (could be you or your neighbors).
• WiFi access points from your neighbors competing for the same channels. Option-Click -> menu bar WiFi icon -> Open Wireless Diagnostic -> Window (menu) -> Scan. This will display all the WiFi access points your Mac can see (grow the window to see all the columns). You can see the RSSI (signal strength) and Noise for all the access points as seen by your Mac. A low negative value is a STRONG signal (-30 would be VERY STRONG), and a high negative value would be a weak signal (-70 or -80 is very weak). What you want to see is that your RSSI is strong, and your Noise is weak. And then looking at your neighbor's RSSI and Noise, you want weak RSSI and still want weak Noise. If you find a strong RSSI on a neighbor's access point, check their channel and your channels. The 2.4GHz frequences should have 5 channels of sepearation as 2.4GHz overlaps the 2 above and the 2 below, so you want to be 5 away from anyone else if you can, or at least sharing a channel with someone that has a very weak RSSI. The 5GHz channels when usng 20MHz do not overlap. When using 40MHz 2 channels are being use, 40MHz would be 4 channels, etc... Again, either 5GHz channel to yourself, or a shared channel where the neighbor has a very weak RSSI. NOTE: Noise can be from other WiFi access points, cordless phone/baby monitors, USB3 devices, Microwaves, etc... Noise is interfererence with your RSSI signal.

Option-Click -> menu bar WiFi icon -> Open Wireless Diagnostic -> Window (menu) -> Performance, will show you a real-time graph of your WiFi signal. Moving around the house with this display up can show you storng or weak WiFi areas of your home.

I have some suggestions with respect to your ssh connections. It is not a cure, but it might be useful.

In your $HOME/.ssh/config file add the following:

Host *
    ServerAliveInterval 300
    ServerAliveCountMax 2

This will help keep ssh connections from A) being seen as idle, which can cause some 3rd party monitoring software to decide to kill the connections, and B) allow ssh to survive short network interruptions.

Feel free to drop the 300 seconds to something lower, but I would not really go below 60 seconds. Adjust the ServerAliveCountMax count accordingly. But huge values can make it difficult to get control of a Terminal window if the other side has gone away, and you need to do something in that window. If you do hit this, then <return> ~ . (return key, tilda key, period key) is the ssh kill connection sequence.

The 2nd thing I'm going to suggest is that you run tmux (or GNU screen) on your remote system. These utilities keep remote sessions alive when the network connection is broken, and you can make a new connection and re-attach to the still running sessions and pick up where you left off.

I have been living in ssh connections for the past 18 years at work. I use a Mac, but I develop software on Unix/Linux systems. At one time I used GNU screen to protect my remote sessions. I have switched to using the newer more flexible tmux. These remote utilities protect me from network interruptions (company forces the VPN connections to disconnect very 24 hours), or I have a power failure that takes out the network, or I need to reboot my Mac, etc... None of these things bother the remote GNU screen or tmux connections.

There are a lot of good tmux YouTube.com presentations.

• • Try this one <https://www.youtube.com/watch?v=wKEGA8oEWXw>
  • Then search for others using "tmux" as your YouTube.com search string.

These are rather good using 'GNU screen' YouTube videos:

• • <https://www.youtube.com/watch?v=I4xVn6Io5Nw>
  • <https://www.youtube.com/watch?v=3S3I9lT6eKE>

Again, the .ssh/config settings and the tmux/GNU screen suggestions are not cures, but they can help improve working with ssh in a network environment where "Stuff Happens" 😁

hyphenistic wrote:

Ethernet is not an option. I've been pure wi-fi for years now. I'm also using WiFi6 over 5 Ghz so I don't think there's an interference issue. I've not been able to find the real-time graph yet. All I can get so far is a wizard that will create a report or capture live performance for a report. No graph though. I'll keep looking.

Wireless Diagnostics -> Window (menu) -> Performance.

You have to click on the "Window" menu and select "Performance"

And looking at the Wireless Diagnostics -> Window (menu) -> Scan, can tell you about "Noise" (aka interference) on each channel. 5GHz can still have interference from neighbor's WiFi access points, unless you live miles from anyone else.

And because software can break, it is possible this is a macOS Ventura issue. And if that is the case, there is not much this user-to-user technical support forum can do about it, except suggest workarounds.