Internet issues on Monterey

Confirming that this is an issue relating to Cisco AnyConnect VPN software. Removing the software from my system running 12.3 has resolved all my DNS issues. This needs to be reported to Cisco.

Try disabling IPv6: System Preferences -> Network -> [Select your network interface in left column] -> Advanced -> TCP/IP -> IPv6 -> Link-Local Only

On Mac 1 download and run Etrecheck.  Copy and paste the results into your reply. Etrecheck is a diagnostic tool that was developed by one of the most respected users here in the ASC and recommended by Apple Support  to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

IMPORTANT:

Before running Etrecheck assign Full Disk Access to Etrecheck in the Etrecheck's Privacy preference pane so that it can get additional information from the Console and log files for the report:

Also click and read the About info to further permit full disk access.

Copy the report

and use the Additional Text button to include the report in your reply.

I didn't go into too much detail, but 16383 is the default ephemeral port range on macOS, which these sockets use. When you hit that number in ephemeral ports, you will have problems. You can have more than that number if those are ports outside the range.

In reality, the number produced by that Terminal command will be higher than 16383 before you run into problems, but in my case, only slightly. My system currently reports about 6000 sockets. The vast majority of those - more than 5000 - are lingering UDP sockets created by AnyConnect, each with an associated unique ephemeral port number, i.e., one of the 16383 possible ports.

93966 is pretty high; however, by removing the | wc -l at the end, you should be able to see the actual list. You can't have more than 65535 ports open in total, so there must be duplicates or thousands of *.* in there.

I had the same problem. This is what worked for me:

In the System Preferences --> Security and Privacy --> Firewall I had blocked emlog.pl from receiving incoming connections. After allowing incoming connections, everything started working again.

I lost DNS access again after a reboot on 12.2. This time, I set 2 of 3 Cisco AnyConnect packet filters to inactive, and everything jumped back to life again. So, at least in my case, things probably are better with 12.2 (I'd tried a similar technique before in 12.1 to no avail), but AnyConnect is still giving me hassles.

Solution given by jpwismer worked for me! Thank you!

Quoting:

In a nutshell, the solution that worked for me:

Go into the Applications folder and open the Cisco folder.

Delete the Cisco Socket Filter application but NOT the Anyconnect client.

My organization is having this issue too, on all Macs running Big Sur and Monterey (12.5 and 12.6 both), although we're seeing it with TCP ports. The Mac will eventually use up and close all available ephemeral ports and not allow any more internet traffic.

Once it hits this threshhold, the only solution is to reboot the device to clear all the closed ports. By increasing the number of available ephemeral ports, you can once again get TCP traffic, until those new ports are exhausted as well. This occurs on any Mac running Big Sur / Monterey, including ones that ONLY have JAMF installed (no other applications or security tools).

We've been working on this internally for several weeks now, with no help from Apple other than to escalate us 3 times, then tell use we need to pay $700 to escalate to the needed level, (their "cross platform engineering" team).

Thank you for this tip re: AnyConnect. I uninstalled (since we no longer use for work) and my machine instantly started working again. It’s been MONTHS of issues. Who knew this would be the culprit?

Deleting Cisco Socket Filter app also fixed for me.

On my Mac M1 Mac Book Air I had go in System Preferences->Network pane and create a new name

(don't worry a custom name (will act just like automatic) and create you home named location and apply it to save the change by hitting the Apply button!

Appears to be an issue with Monterey from my tests. I rolled back to Catalina on my early 2015 MacBook Pro, and I'm getting the usual fast speeds again https://discussions.apple.com/thread/253335091?answerId=256242908022#256242908022

Simon, I totally agree. I have found the same, the only way to fix the issue is to erase the Mac completely and then do a fresh Monterey install (it seems to be the upgrade to Monterey from Big Sur causes the issue). Just doesn't do it on all Macs.

Similar issues here, as well.

I opened another thread here:

https://discussions.apple.com/thread/253371433

But this one seems to be the most prevalent on the issue at hand for many of us... My Situation:

Upgrade to Monterey OSX brought about frequent loss of broadband connection

Since upgrading to Monterey OSX, my Mac Mini has been losing broadband connection several times a day. Prior to the upgrade both wireless and broadband connection were rock solid. It does not lose wireless connection to the router, just the broadband feed regardless of whether I am on wired/ethernet or on WiFi.

Since upgrading the connection is dropped at least 5X or 6X per day. Reboot solves it for a while but eventually it drops broadband again forcing yet another reboot. It's getting tedious.

Running Currently: Monterey OSX version 12.1 on a Mac Mini (M1, 2020), 16GB Ram.

I had hopes the V12.1 upgrade might help, but alas it is no better.

I have had success keeping connected when I don't open Apple Mail and/or Readdle Spark. MS Outlook does not seem to engender the issue. Once I boot up either Mail or Spark applications - I have what appears to be a DNS issues and lose broadband in any open browser (Chrome, Safari, etc).

My machine is for work and we use Cisco AnyConnect sometimes to access certain portals (maybe once every couple of weeks). When I go into 'Network' panel in System Preferences I notice there are three Cisco AnyConnect Socket Filters open and connected. there is also a 'MS Defender ATP Content Filter' connected and running. Of course the WiFi connection is there too. We use typical array of MS Office apps and comms tools like WhatsApp, Signal, et al but nothing exotic and we rarely VPN in (just as mentioned above).

I have tried all the DNS flush advice and different suggested configs within this thread, but to no avail. Kind of disheartening as I was leaving my rig on for weeks at a time with the previous OSX.

Appreciate any help on this!

Best,

Mike