Browsers on my iMac are taking several minutes to connect to https sites

Hi jec-acc,

You've done some great troubleshooting so far. We have another step which can help with this issue. What we want to do is try starting up in safe mode, as safe mode does some system checks, and can sometimes resolve issues. Use safe mode on your Mac - Apple Support

It may take longer to finish the start up, and you'll also see some differences in the display. This is expected with safe mode, and when you restart normally, they'll be gone.

Test, and then restart normally and test again.

If still having the issue, anything change around that August 20th date? Such as a VPN or security software added?

Let us know how safe mode goes, and the answers the last questions, if still an issue.

Take care!

Please download and run EtreCheck and share the resulting report to the clipboard. Then open a new reply here, and press the Additional Text button (that looks like a printed page) to get a text input box big enough to paste the hardware and software configuration report here, and paste and post that report here.

An add-on first-few-hops VPN client package is a good potential culprit as was mentioned above. Other options for culprits can include add-on anti-malware packages, and add-on security apps. Hardware problems are also a possibility.

Firefox has its own certificate chain and its own certificate store and AFAIK its own SSL/TLS/HTTPS implementation and does not depend on (most of) macOS for that, which means this probably isn’t involving the local certificate store.

And DNS is typically not slow for just HTTPS.

Is the iMac connected to the internet via Wi-Fi, or wired Ethernet, or both?

If this is happening your own network, also check the Wi-Fi router firmware and update that to the most current, and restart that device. That’s probably not the issue here, but I’ve also seen (buggy, confused) Wi-Fi routers get recalcitrant with specific Wi-Fi clients.

If the primary (1st) DNS server is malfunctioning (or having difficulties with just your Mac), then the Mac will wait for the DNS request to timeout before it will try the secondary DNS server.

Try using System Settings -> Network -> Click on you Network Interface (most likely WiFi or Ethernet) -> Details -> DNS (tab) -> [+] and add DNS server addresses.

Some suggestions for Experimentation:

1.1.1.1 (Cloud Flare)

8.8.8.8 (google)

208.67.222.222 (OpenDNS)

All of the above should have fast reliable DNS lookups.

You can always use the [-] button to remove the DNS servers after you have experimented with them.

Although troubleshooting DNS is a great start, based on what you provided in your post, and your own findings, that is not the likely culprit here.

When you attempt to connect to a secured website, does your browser show, for example, a slash thru the address bar padlock? This could mean either the site you are accessing OR your Mac could be exhibiting mismatched or outdated security certificates/protocols.

With that said, here are some potential reasons:

• As you are aware, https uses the TLS cryptographic protocol to make a secure connection. Could it be possible that the version of TLS is outdated on your Mac? Not likely, but maybe possible. I believe the current version is TLS 1.3.
• Associated with these protocols are certificates. One or more of these may be missing or corrupted. AFAIK, these are typically updated when Apple releases a security update.

So what may be causing this delay. Trying to not go into too much boring mumbo-jumbo that following it the basic communication that goes on when you attempt to access a secured website:

At the beginning of the connection, a process called a handshake occurs. During this process, the your Mac authenticates the website's server’s TLS certificate and the two decide on a mutually supported cipher suite. Cipher suites are a collection of algorithms that all work together to securely encrypt your connection with that website. When that suite is negotiated, that’s when the version of the TLS protocol and the supporting algorithms are determined. The certificate just facilitates the process ... so you can see where this can go astray and take more time than necessary.

jec-acc wrote:

I think I started in safe mode, it's not obvious that it's in safe mode. It's going to take some time to find the installation media; I don't recall seeing a dvd or other media containing Ventura. We must have updated online?

See the section entitled “Verify your Mac started up in safe mode“ to verify the Mac is booted into Safe Mode:

… Start up your Mac in safe mode - Apple Support

Here is the Intel iMac Recovery usage: Use macOS Recovery on an Intel-based Mac - Apple Support

Check for firmware updates for the Wi-Fi router, see if the WiFi Explorer or similar Wi-Fi scanning app finds any obvious issues.

Open DNS excellent servers:

It's been a long, long time since Apple provided their operating systems on CD ... so, yes, it would have to be downloaded from the Apple servers over the Internet via the Apple App Store on your Mac.