MacBooks (wifi) cannot 'see' each other or Mac Pro (wired) after El Capitan upgrade

Discussion in 'OS X El Capitan (10.11)' started by SamB_, Feb 1, 2016.

  1. SamB_ macrumors newbie

    Feb 1, 2016
    Since upgrading my two MacBooks (Air and Pro) and Mac Pro (old tower style) systems to El Capitan, I cannot connect my laptops to my Mac Pro. Months have gone by with all attempted solutions (via web research) failed.

    My MacBooks cannot see ANYTHING else on the network.

    From either of my MacBooks, via wifi:

    • I cannot print to printers.
    • I cannot see other MacBooks.
    • I cannot see my Mac Pro tower (it is connected to the network via wired connection, which connects to my Airport Extreme)
    • I cannot see my Mac Mini (connects to network via wired connection, STILL CONNECTS to the Mac Pro (also wired connection only), runs on 10.7.5 b/c it's too old to update)

    From my Mac Pro and Mac Mini:

    • I cannot see either Macbook
    • Mac Mini and Mac Pro CAN see each other

    BUT, the Mac Pro tower has unsolvable problems with Keychain, and cannot connect to email accounts, or does so sporadically with some success. The Keychain issue has also absorbed hours of my life, and is also without a solution. Perhaps it is a related issue, I do not know.

    Can anyone please help? I am taking great pains in restraining all forms of venting/ranting for the sake of productivity, but I am truly at wits end. Thanks in advance for help solving this...
  2. JohnDS macrumors 65816

    Oct 25, 2015
    Double check the IP addresses of all computers to make sure they are all on the same subnet and have the appropriate subnet masks. (Someone recently reported a similar problem and discovered he had inadvertently set the subnet mask to instead of on a 192.168.x.x subnet).

    Can you ping the Pro from the laptops? Can you run a trace route?

    Do you have "connected servers" ticked in the General and Sidebar tabs of the Finder Prefs on all computers?

    What are you using for a router? Have you checked the DHCP logs on the router?

    Are all the devices connecting via DHCP?

    Also, can all computers connect to the internet?
  3. SamB_ thread starter macrumors newbie

    Feb 1, 2016
    Thanks, I will look into this this afternoon. I did make some changes to the IP at one point per other suggestions out there, and that change may be part of the problem.

    Initially upon installing El Cap, my MBP could see my Mac Pro (it would show as available in the sidebar) via wifi, but it would not actually connect.

    Now, the MP and MBP no longer see each other at all (in the sidebar or 'browse for server')

    ALL computers connect to the internet just fine, and always have.

    The only other thing worth mentioning is the Mac Pro is sometimes connected to the internet via "Private Internet Access" VPN service. Prior to El Cap, that did not create any local networking problems whether it was on or off, and the PIA software is up-to-date. Again, though, the local network connection problem remains even if the PIA software is turned off completely (i.e. via full shutdown and cold start).

    I feel like the problem is on the wifi end with the MBP and MBA, as neither laptop sees the network printer anymore either (which is also a wifi setup). The MP only prints to the printer if it is connected via USB.

    Also, I used to be able to see my Mac Mini just fine from all computers, and it (wired connection too, like MP) is no longer visible to the laptops, and it cannot see the laptops or wifi printer either (although it still connects to the MP tower via Cat6).

    Thanks very much for any further thoughts.
  4. SamB_ thread starter macrumors newbie

    Feb 1, 2016
    Right now I'm focusing on the MacBook Pro and the Mac Pro tower (for the following):

    Subnet masks are on both machines.

    I can ping the Mac Pro from the MBP successfully, but the Mac Pro tower cannot see the MBP laptop (no packets received)


    Current Gen Airport Extreme Base Station (never had any issues with it, changed nothing with El Cap upgrade)

    I do not know how to check DHCP logs on the router or what they would mean if I did... suggestions?


    Yes, all are connected to the internet.

    Thanks for any further help.
  5. Alrescha macrumors 68020

    Jan 1, 2008
    This seems like a pretty impossible situation unless there is a firewall involved*. I would check the firewall settings on all of these machines.


    * I am assuming there is only one Mac Pro. You sometimes say "Mac Pro" and sometimes "Mac Pro tower" so it is hard to be sure.
  6. SamB_ thread starter macrumors newbie

    Feb 1, 2016
    I just noticed that my MBP was connecting via the lower frequency network band. When I switched to the 5Ghz network (via the same Apple Airport Extreme Router) suddenly the MBP could browse files on the Mac Pro Tower.

    Also, the MP tower then showed the MBP as a 'connected server' in the sidebar, but it failed to connect, and then Finder kicked the MBP off the 'connected servers' list in the sidebar. The MP still cannot ping the MBP (request timeout 10x).

    So, there is still a problem of some sort.
    --- Post Merged, Feb 4, 2016 ---
    Sorry, yes there is only ONE Mac Pro involved. I was just trying to keep things from being confused as Mac Pro and MacBook Pro sound so similar.

    Right now I am just troubleshooting the MP and MBP connection. (there is also a Mac Mini running 10.7.5 and a MacBook Air running El Cap, but I'll worry about them later.)
    --- Post Merged, Feb 4, 2016 ---
    Firewall is ON on both machines.

    File Sharing (AFP) is set to allow incoming connections on the MP
    File Sharing (AFP, SMB) is set to allow incoming connections on the MBP

    Presuming the next suggestion is 'turn off Firewall', I did that. The MBP reappeared in the Finder sidebar, but it will not connect. "Connect As" is unresponsive (button appears to 'click' (turns darker gray) but the usual popup window never appears.

    I still have the same ping failure when the MP tries to connect to the MBP. I did not reboot
  7. Alrescha macrumors 68020

    Jan 1, 2008

    Pings and their replies are the same kind of packets, so it is pretty unlikely (like impossible) for machine 'a' to be able to ping machine 'b' but not the other way around unless there is a firewall of some kind involved. This could be on the machines, or some odd behavior of the router.

    Other things that come to mind:

    do you have more than one router with wifi? For instance your Airport and your ISPs device?

    do you have a guest network on your Airport?

  8. SamB_ thread starter macrumors newbie

    Feb 1, 2016
    The only network gear I'm using is the cable modem (no wifi capability), an ethernet hub, and the Apple Airport Extreme Base Station.

    The Mac Pro is connected to the network via Cat 6, as is the Mac Mini (and they can talk to each other fine). Only the laptops connect wirelessly, and the wired MP and MM cannot see the laptops (via wireless)

    It is very odd that the MP cannot ping the MBP, but the ping goes through fine in the other direction (regardless of firewall settings).
  9. Alrescha macrumors 68020

    Jan 1, 2008
    Does the cable modem do DHCP? If so, is it somehow not connected to the WAN connection on the Airport? (and something else is?).

  10. SamB_ thread starter macrumors newbie

    Feb 1, 2016
    I don't know what the cable modem does (DHCP or not).

    The cable modem is plugged directly into the WAN port on the Airport Extreme, and then one of the AE ethernet connections plugs into a hub where the Mac Pro and Mac Mini connect.

    To be clear, though, the internet (via cable modem) works fine from all computers.
  11. dsemf macrumors 6502

    Jul 26, 2014
    To confirm: MP and MM >(wire)> Hub >(wire)> AE >(wire)> Cable Modem, MBP >(wifi)> AE >(wire)> Cable Modem.

    In the Airport Utility, Network Tab, which Router Mode option is selected?

    It might be useful to see the output of ifconfig and netstat -r for each machine. Put the results in code blocks.


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