Ping Help
The Ping tool tests whether or not a given host
is online. Provide the following information:
- Host name:
The machine name (eg. www.fifi.org) or an IP address
(eg. 127.0.0.1) to probe.
- Packet count:
The number of packets to send to the given host. If you choose
to send more than one packet, you'll be able to get some statistics,
like what was the fastest and longest trip.
- Time between packets:
The delay in seconds between each packet to be sent.
- Format results:
You can elect to see the raw (unformatted) ping output, or a
table summary.
If you choose to get formatted results, the table has the following
fields:
- Sequence number:
The number the packet had when sent. If an host is far away, or
if it's busy, some packets might be swapped, and will arrive in a
different order than when sent (which is generally not a good sign).
- Answer from:
Lists the host address of the machine which answered the ping. If
the pinged host is behind a firewall, the firewall might answer for
it.
- Time To Live (TTL):
The number of gateways or routers a packet is allowed to go
through before being destroyed (hence avoiding loops). Generally,
when a host answer to the ping, it sets the return packet's TTL to
255 (or 64 for more recent machines or operating systems). Subtract
the TTL as shown from 255 (or 64) to get the number of gateways and
routers crossed by the packet. If the shown TTL is less than 64, you
can assume the base number for subtraction to be 64 since an ICMP
packet crossing more than 200 routers is still to be seen! You can
get the names of these gateways and routers with traceroute tool.
- Delay:
Time taken by the round trip. The figures are in milliseconds.
- Statistics (packets sent, received, and loss;
minimum, maximum and average delays):
These should be self-explanatory.
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