Really Fast ICMP Echo Requests

Today I was helping a client troubleshoot some odd network behavior. He reported that he had no network connectivity. Not knowing exactly what he meant by that, I decided to ping his computer from one of the servers at the same location. What followed next was pretty interesting.


C:\Documents and Settings\administrator>ping mob05

Pinging mob05.myclient.local [192.168.24.39] with 32 bytes of data:

Reply from 192.168.24.39: bytes=32 time=-5ms TTL=64
Reply from 192.168.24.39: bytes=32 time=-5ms TTL=64
Reply from 192.168.24.39: bytes=32 time=-5ms TTL=64
Reply from 192.168.24.39: bytes=32 time=-5ms TTL=64

Ping statistics for 192.168.24.39:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = -5ms, Maximum = -5ms, Average = 1073741819ms

C:\Documents and Settings\administrator>ping mob05

Pinging mob05.myclient.local [192.168.24.39] with 32 bytes of data:

Reply from 192.168.24.39: bytes=32 time<1ms TTL=64
Reply from 192.168.24.39: bytes=32 time<1ms TTL=64
Reply from 192.168.24.39: bytes=32 time<1ms TTL=64
Reply from 192.168.24.39: bytes=32 time<1ms TTL=64

Ping statistics for 192.168.24.39:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms0

C:\Documents and Settings\administrator>ping mob05

Pinging mob05.myclient.local [192.168.24.39] with 32 bytes of data:

Reply from 192.168.24.39: bytes=32 time=-15ms TTL=64
Reply from 192.168.24.39: bytes=32 time=-14ms TTL=64
Reply from 192.168.24.39: bytes=32 time=-5ms TTL=64
Reply from 192.168.24.39: bytes=32 time=-14ms TTL=64

Ping statistics for 192.168.24.39:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = -15ms, Maximum = -5ms, Average = 1073741812ms


I know that some driver issues can cause negative response times, and my initial suspicion was something related to a clock issue, but still, seeing a -15ms ping response struck me as blog-worthy.

Leave a Reply