Cannot share screen without disabling firewall in Ventura

Troubleshooting update:

Referencing my above reply, some more data points.

• Netstat run on the MB Air shows it is listening on port 5900 for both tcp4 and tcp6 (for VNC connection).
• Wireshark shows continuous SYN packets from non-Ventura system to port 5900 on the MB Air being completely ignored when attempting screen sharing.
• Doing the reverse (screen sharing from non-Ventura system to MB Air) Wireshark shows successful connections to port 5900 of those systems and screen share works.

So something broke with the upgrade from 13.2 to 13.2.1 with regards to answering on port 5900.

Asking Apple here to please fix with next upgrade to Ventura!

Hello NathanCG,

Thanks for reaching out to Apple Support Communities. We see you have some questions about screen sharing, and disabling firewall, and we'd like to help. Let's test a few different places on your Mac, to see if this happens there as well, as this can help isolate the issue more.

From here, try creating a new user on your Mac, to let us know if you're seeing this there: Add a user or group on Mac

Add a user

1) On your Mac, choose Apple menu  > System Settings, then click Users & Groups  in the sidebar. (You may need to scroll down.)

2) Click the Add Account button below the list of users on the right (you may be asked to enter your password.)

3) Click the New Account pop-up menu, then choose a type of user.

•Administrator: An administrator can add and manage other users, install apps, and change settings. The new user you create when you first set up your Mac is an administrator. Your Mac can have multiple administrators. You can create new ones, and convert standard users to administrators. Don’t set up automatic login for an administrator. If you do, someone could simply restart your Mac and gain access with administrator privileges. To keep your Mac secure, don’t share administrator names and passwords.

•Standard: Standard users are set up by an administrator. Standard users can install apps and change their own settings, but can’t add other users or change other users’ settings.

•Sharing Only: Sharing-only users can access shared files remotely, but can’t log in to the computer or change settings. To give the user permission to access your shared files or screen, you may need to change options in File Sharing, Screen Sharing, or Remote Management settings. See Set up file sharing and Share the screen of another Mac.

For more information about the options for each type of user, click the Help button in the lower-left corner of the dialog.

4) Enter a full name for the new user. An account name is generated automatically. To use a different account name, enter it now—you can’t change it later.

5) Enter a password for the user, then enter it again to verify. Enter a password hint to help the user remember their password.

6) Click Create User.

7) Depending on the type of user you create, you can also do any of the following:

•For an administrator, select “Allow user to administer this computer.”

•Select “Allow user to reset password using Apple ID.” To use this option, the user must have set up iCloud on this Mac. However, this option isn’t available if FileVault is turned on and set to allow the user to reset their password at startup using their Apple ID.

•Use Sharing settings to specify whether the user can share your files and share your screen.

For information about Apple’s privacy policy, see the Apple Privacy Policy website.

If your Mac or Magic Keyboard has Touch ID, a new user can add a fingerprint after logging in to the Mac.

Let us know, and we'll go from there.

Regards.

Good afternoon NathanCG,

It might be helpful for you to speak directly with an Apple advisor about this issue. Click the link below, choose the phone number for your region from the list, and call when it is convenient.

Contact Apple for support and service - Apple Support

Take care.

Same thing for me only disabling firewall has no effect.

I was sharing screen from a MB Air M2 (Ventura 13.2) to main setup (Mac Mini, High Sierra, two 27" screens), which was working perfectly fine until I updated the MB Air to 13.2.1. Now screen sharing will not work, altho file sharing still works just fine. It works in reverse, i.e., on the MB Air I can screen share the two 27" monitors from Mac Mini, but sharing two large screen displays onto a laptop is pointless.

All permissions and sharing settings are the same as before the upgrade to 13.2.1.

And all systems have been hard-rebooted (including my gateway/router) in case something needed resetting.