MacBook Pro Can't Receive Pings, but CAN send

Discussion in 'macOS' started by svcghost, Mar 27, 2011.

  1. svcghost macrumors member

    Jul 4, 2010
    Hey guys,

    Can you help me troubleshoot this issue I am having?
    When I try and ping my MB Pro from my Windows PC I can't get any replies. But when I send pings from the MB Pro to my PC I DO get replies.

    Also, I have an Apache web server set up on my MC Pro. I can't connect to the server from the Windows PC.

    Thanks guys
  2. emiljan macrumors 6502


    Jan 25, 2010
    Check your firewall settings. It could be blocking all incoming connections to your mbp.
  3. svcghost thread starter macrumors member

    Jul 4, 2010
    No firewall settings are configured. Allowing all traffic. Any other ideas? By the way I just checked the Firewall settings in the System Preferences > network settings. Is there a way to check if additional or hidden firewall rules are set up?
  4. brijazz macrumors 6502


    Jul 31, 2008
    I know you said that you don't have anything configured in Firewall, but double-check that you don't have "Stealth Mode" enabled (under your Firewall settings). It's the bottom check box (at least on 10.6).
  5. svcghost thread starter macrumors member

    Jul 4, 2010
    Well the Firewall is off, but when I turned it on and checked advanced settings, it said stealth mode was on. So I turned it off, and then tried again, no luck. I turned the Firewall off and no luck.

    Man what can this be.
  6. brijazz macrumors 6502


    Jul 31, 2008
    Now that you've disabled stealth mode, try restarting your machine and see what happens.
  7. whooleytoo macrumors 604


    Aug 2, 2002
    Cork, Ireland.
    Are you certain you're pinging the right address when you're pinging the MBP? Do both machines have the same subnet mask?
  8. locust76, Mar 28, 2011
    Last edited: Mar 28, 2011

    locust76 macrumors 6502a

    Jan 23, 2009
    Both machines only need the same subnet mask if they're on the same network (which they probably are). Since the Windows machine can be pinged, I think it's safe to assume that the TCP/IP settings are correct.

    The firewall (or something else) is blocking ICMP requests, or the MacBook's IP (the one being pinged) is not correct.
  9. ClaytonMcCranor, Mar 28, 2011
    Last edited: Mar 28, 2011

    ClaytonMcCranor macrumors newbie

    Mar 23, 2011
    Horsham, West Sussex, England
    If your systems sit behind a router try pinging the IP of the router.
    see what happens.

    I had a weird one a few months ago. 2 laptops in the same house on the 'same' wireless network. One could ping but the other could not. Turned out one laptop was on next door's unsecured network! wich returned the ping but the other on the stealthy network did its job and did not.

    prob not the same issue but you never know.
  10. whooleytoo macrumors 604


    Aug 2, 2002
    Cork, Ireland.
    I think it would be possible for one machine to be ping-able, but not the other, with a configuration such as:

    PC - IP: Mask:
    MBP - IP: Mask:

    With that subnet mask, the PC would see the Mac as being on the same network and would be able to ping it, but the MBP would not see the PC, thinking it's on a separate network.
  11. svcghost thread starter macrumors member

    Jul 4, 2010
    IPs are correct. Subnet masks are the same. Still trying to figure this out. Remember it's the PC that can't ping the MBP. I CAN ping the PC from the MBP.
  12. svcghost thread starter macrumors member

    Jul 4, 2010
    Anyone else have any idea why this may be happening? Is there a process running that blocks incoming connections or traffic? Anywhere I can go to seek help for this?
  13. torid110, Mar 29, 2011
    Last edited: Mar 29, 2011

    torid110 macrumors regular

    Jan 22, 2006
    Jersey City, NJ
    Have you tried running traceroute to see what hops it's taking to go from your mac to the pc (and vice-versa)? Also, can you ping the mac/pc from itself ?
  14. svcghost thread starter macrumors member

    Jul 4, 2010
    They are on the same network, there is no hop. They are aware of each other. My PC can ping PC2, but not Mac. My Mac can ping PC and PC2. This is very weird. There is definitely something on my Mac that is disallowing ping responses. I just don't know WHAT or WHY.
  15. ScoobyMcDoo, Mar 30, 2011
    Last edited: Mar 30, 2011

    ScoobyMcDoo macrumors 65816

    Nov 26, 2007
    Austin, TX
    For some troubleshooting, you could try this command to see if the packets make it to the mac. In a terminal (on the mac) use this command:

    tcpdump 'icmp[icmptype] = icmp-echo or icmp[icmptype] = icmp-echoreply'

    Then try to ping the mac and look at the output of the tcpdump command. If it is truly blocking IMCP echo requests, you well see a bunch of echo requests, but no echo replies.

    Also, another handy terminal command to make sure that the UI is no lying to you is:

    ipfw list

    If the firewall is truly disabled you will only see the default rule of allow everything.
  16. svcghost thread starter macrumors member

    Jul 4, 2010
    Can't believe I didn't check this sooner..

    I have Check Point VPN-1 SecureClient installed on my Mac to work from home. I thought I had this program turned off, but I guess some of its processes run in the background too. Anyway, all I had to do was disable the security policy that it enforces.

    Sorry guys! Thanks for your feedback and help!

    P.s. Thanks for those commands Scooby. Those would have definitely helped.
  17. nqn4774 macrumors newbie

    Aug 11, 2011

    I have the same problem. Can you show me how to disable the security policy? I use Cisco VPN Client 4.9.01. I can't figure it out where to go to completely disable the firewall on my Mac so I can ping from a PC.
  18. SolidSnak3 macrumors member

    Mar 1, 2011
    What do you guys mean by ¨ping¨? i m really curious of what that do, many have being talking about in this thread but i have no idea what this is and what it does.:D
  19. macrumors newbie

    Oct 31, 2017
    I just spent 3 hours debugging the same f***ing problem. Here's an image on how to disable the stupid Security Policy (right click menu bar icon > Disable Security Policy):

    Turn off security.png
  20. old-wiz macrumors G3

    Mar 26, 2008
    West Suburban Boston Ma
    THE "Ping" is part of the protocol. One system sends a ping to another to find out if it is there, and lack of a response indicates that the other end is gone or busy. You also use ping to see how fast your connection is going.

    Ping is part of TCP (transport control protocol)

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