When your
connection attempts to a remote machine fail with time-outs, "host unreachable" and "network unreachable"
errors, you can check the connection between your
local machine and the remote with the
ping command.
The ping command sends an ICMP Echo Request message (ICMP stands for Internet Control Message Protocol). This message asks the remote machine to send an echo reply that includes the sent message data. If the remote machine's networking software is functional, it will reply.
How to use ping:
UNIX:
> Ping www.everything2.com 100 10
PING www.everything2.com: 100 byte packets
100 bytes from 206.170.14.131: icmp_seq=0 time=63ms
100 bytes from 206.170.14.131: icmp_seq=1 time=109ms
100 bytes from 206.170.14.131: icmp_seq=2 time=140ms
100 bytes from 206.170.14.131: icmp_seq=3 time=47ms
100 bytes from 206.170.14.131: icmp_seq=4 time=78ms
100 bytes from 206.170.14.131: icmp_seq=5 time=141ms
100 bytes from 206.170.14.131: icmp_seq=6 time=32ms
100 bytes from 206.170.14.131: icmp_seq=7 time=63ms
100 bytes from 206.170.14.131: icmp_seq=8 time=140ms
100 bytes from 206.170.14.131: icmp_seq=9 time=32ms
www.everything2.com PING statistics--
10 packets transmitted, 10 ackets received, 0% packet loss
round-trip (ms) min/av/max = 14/72/140
Windows NT:
C:> ping www.everything2.com
Reply from 206.170.14.131: bytes=32 time=63ms TTL=241
Reply from 206.170.14.131: bytes=32 time=109ms TTL=241
Reply from 206.170.14.131: bytes=32 time=140ms TTL=241
Reply from 206.170.14.131: bytes=32 time=47ms TTL=241
Reply from 206.170.14.131: bytes=32 time=78ms TTL=241
Reply from 206.170.14.131: bytes=32 time=141ms TTL=241
Reply from 206.170.14.131: bytes=32 time=32ms TTL=241
Reply from 206.170.14.131: bytes=32 time=63ms TTL=241
Reply from 206.170.14.131: bytes=32 time=140ms TTL=241
Reply from 206.170.14.131: bytes=32 time=32ms TTL=241
Notes: If your packet loss is high, the connection
is not getting through somewhere along the
path.
If you lost a connection, try the ping command. Usually, if you wait for a few minutes, the connection will re-establish. Run an occasional ping to see when the connection is available.