[ratlater]

At the University here we have noticed a peculiarity with OS X dropping pings on a regular and repeatable basis. I've tested this on two different machines running 10.2.4 on two very different networks. One is using airport and the other a physical ethernet connection. To make this brief OS X is always dropping the 101st packet on extended ping sessions.

To test this, use this command:

Code:
ping -c 1000 your.ip

You will need to run this from another machine. After it finishes post the bottom line:

1008 packets transmitted, 1000 packets received

To anyone who has greater knowledge of OS X's network stack, is there any reason why it would be dropping ping packets like this? Does the OS deny priority to ping packets after a certain number?

thanks,
-matt

[coolmacdude]

It doesn't drop any for me (at least locally, using 127.0.0.1), but why in the world would you need to ping someone 1000 times?

[ratlater]

Originally posted by coolmacdude:
It doesn't drop any for me (at least locally, using 127.0.0.1), but why in the world would you need to ping someone 1000 times?

The problem won't appear of the loopback interface (127.0.0.1). You usually don't need to ping something 1000 times, the point is the OS is dropping packets in a repeatable and predictable pattern. If it is only ICMP ping traffic that is fine, but if it is dropping packets from all traffic on a regular basis that is bad and needs to be fixed.

-matt

[Gul Banana]

Did this
No packets dropped
And it was across the Internet, too

[someone_else]

Ummm, ICMP does not run over TCP, or UDP. It is built directly on top of the IP stack. It's technically not part of IP, but most people think of that way.

So the problem is not in TCP, and I doubt very much it's with IP either. I would say with 99% certaintity that the problem lies in your network config..

[macmike42]

I thought this was going to be about that new TCP/IP Evil Bit feature.

[bzImage]

if you ping to 127.0.0.1 or your own ip from your own machine, you are doing nothing, the packet never reach the network card it goes directly to the loopback driver wich its loaded on memory.

Try to trace the route of the pings i mean:

From other machine

traceroute <your_mac_ip>

note: if the other machine its a windows pc from the dos prompt use "tracert" instead of "traceroute"

to check if there its a router or something loosing the pings, or try a crossover cable between 2 machines (no hub, no switch just the 2 machines) and ping from one to the other, it still looses packets ?