Mac OS X Yosemite connectivity issue

Networkpingterminal

Every so often my MacBook Pro starts getting very intermittent network connectivity. I have a Virgin Media SuperHub.

Pinging my router gives me lots of request timeouts:

64 bytes from 192.168.0.1: icmp_seq=2438 ttl=64 time=2.000 ms
64 bytes from 192.168.0.1: icmp_seq=2439 ttl=64 time=33.810 ms
Request timeout for icmp_seq 67976
Request timeout for icmp_seq 67977
Request timeout for icmp_seq 67978
Request timeout for icmp_seq 67979
64 bytes from 192.168.0.1: icmp_seq=2444 ttl=64 time=1.568 ms
64 bytes from 192.168.0.1: icmp_seq=2445 ttl=64 time=1.633 ms

Sometimes the timeouts last only a few pings sometimes many.

Through experimentation I've found that flushing the arp cache using

sudo arp -a -d

Immediately max ping start working but then after a bit the timeouts come back. I've confirmed this by doing:

sudo watch -n 1 arp -a -d

And the ping timeouts disappear and I can browse without any slowness as long as I leave that running.

Rebooting the computer also clears this problem for a while but it comes back.

I need a permanent fix for this.

Best Answer

Try this:

http://www.macstadium.com/blog/osx-10-9-mavericks-bugs/

Even if supposedly only applies to Maverick, I found a Macbook with Yosemite having the same problems and the fix seemed to work. Worth a try.

Related Solutions

Mac mini with intermittent wifi connnectivity problems

Sometimes that is caused by WiFi Chanel overcrowding.

Try changing the WiFi channel for Mac Mini.

Cannot ping between OS X on wireless LAN

First, it seems your wireless router seems to have some firewall part preventing ICMP messages (ping is one part of this protocol suite) going over the wireless lan to prevent a ping flood. To verify this, try out these tests:

Disable any VPN software you may run (VPN software mostly includes Desktop policies preventing "unwanted" protocols to be executed and they insert special routes).
ping -c2 192.168.0.255

A usual behaviour for that command would be to get an answer from all your machines in the same network. If this doesn't work, something else is preventing that. As you wrote you disabled all the OS X firewalls, this command should be successful.

To verify this, go to step 2:

Take two MBP and connect them with one CAT6 Gigabit Ethernetcable and assign IP adresses to the LAN ports:

MBP1: en0: 172.16.42.5 netmask 255.255.255.0

MBP2: en0: 172.16.42.6 netmask 255.255.255.0

MBP3: en0: 172.16.42.7 netmask 255.255.255.0

Now try to ping MBP2 from MBP1 and vice versa and take notes:

MBP1 -> MBP2: 1->2 yes / no, 2->1 yes / no

MBP1 -> MBP3: 1->3 yes / no, 3->1 yes / no

MBP2 -> MBP3: 2->3 yes / no, 3->2 yes / no

If all of these connections are working, then you know the router is the bad guy. Take a closer look in your router configuration and look there for terms like "broadcast storm", "ping flood" or "ICMP broadcast prevention". Switch that feature off and try it again.

Hope this helps in analysing your annoying trouble. :-)

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