Why can I not ping to external networks?

Zhong Jiang November 22, 2012

I have network-manager installed to replace the utilization of /etc/networking, which is the default interface to configure networks.

However, I was reading this guide on modifying the sysctl.conf file and have added many additional lines for TCP/IP tweaks and recommended settings. I’m uncertain if the settings will impact the network-manager or only reach to /etc/network.

Then I was testing out the settings and discovered that I cannot ping to an external network.

Why is the settings not working?

  1. Rohit Pandey
    December 6, 2012 at 4:52 pm
  2. Jim Chambers
    November 24, 2012 at 12:26 am

    Were you able to ping these IPs before changes?

    • Zhong Jiang
      November 24, 2012 at 3:51 am

      I have no idea, it was given to me on a guide I read about tweaking sysctl.conf.

  3. Rakesh Mishra
    November 23, 2012 at 7:48 am

    U CAN TRY videos available on youtube for ur related question

  4. Thomas Chandra
    November 23, 2012 at 4:55 am

    Sounds like problem with IPv6 and IPv4 config/compatibility

  5. ha14
    November 22, 2012 at 7:37 pm

    Linux disable or drop / block ping packets all together
    To enable ping request type the command:
    echo "0" > /proc/sys/net/ipv4/icmp_echo_ignore_all

    perhaps to enable Enable packet forwarding via the sysctl.conf and /or via /etc/sysconfig/network

    OpenVZ Server Can Not Ping?

    • Zhong Jiang
      November 23, 2012 at 12:34 am

      Sorry, but none of the links helped and I'm not sure why do I need to use those commands. I can ping addresses internally, such as google or yahoo.com but with addresses like:, I cannot ping them.

      • ha14
        November 23, 2012 at 9:53 am

        perhaps you have to delete some lines sysctl.conf.

        Multiple NICs, single IP

        • Zhong Jiang
          November 24, 2012 at 3:50 am

          I'm using Network Manager to connect to my wireless network, the network interfaces will be ignored. I have deleted some invalid keys identified on boot.

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