An ICMP ping is a low-level, very small packet exchange:
xymon: Hey, server1
server1: what??
xymon: <wanders off>
On the other hand, ssh should be setting up and tearing down an encrypted
connection, even though it doesn't actually login. I assume there would be
multiple packets bouncing back and forth, agreeing on an encryption
protocol and swapping keys, or whatever. I'm not very surprised that it
takes longer than a ping to complete the connection.
Ralph Mitchell
On Mon, Aug 24, 2015 at 11:04 PM, Jeremy Laidman <user-71895fb2e44c@xymon.invalid>
wrote:
I've noticed the same thing on many of my servers. Without really
thinking about it, I just assumed that the xymonnet TCP connection
measurements were taking into account (removing) network latency time, and
only giving the latency within the server being tested. Thinking about it
now, I'm not sure how xymonnet would do this.
Yes, I believe xymonping uses ICMP. You can run xymonping directly like:
sudo -u xymon /usr/lib/xymon/server/bin/xymonping 10.100.2.17
and see how it compares with the graph, or "ping" or "time telnet
10.100.2.17 22 </dev/null".
J
On 25 August 2015 at 08:02, Shawn Heisey <user-5d0d01dba542@xymon.invalid> wrote:
Here is a "connection times" graph from Xymon:
https://www.dropbox.com/s/voyqnzfnsqaact9/xymonresponsegraph.png?dl=0
This shows "conn" times in the 40 millisecond rang, and "ssh" times in
the 200 microsecond range.
What is the source of the "conn" graph? I would have guessed ICMP, but
it doesn't make any sense for a ping to take longer than an ssh
connection, especially not that much longer. This is what I get if I
ping that machine from the xymon server ... it doesn't take anywhere
even CLOSE to 40 milliseconds:
[root at mcp xymon]# ping palazzo
PING palazzo.REDACTED.com (10.100.2.17) 56(84) bytes of data.
64 bytes from palazzo.REDACTED.com (10.100.2.17): icmp_seq=1 ttl=62
time=0.572 ms
64 bytes from palazzo.REDACTED.com (10.100.2.17): icmp_seq=2 ttl=62
time=0.582 ms
64 bytes from palazzo.REDACTED.com (10.100.2.17): icmp_seq=3 ttl=62
time=0.573 ms
64 bytes from palazzo.REDACTED.com (10.100.2.17): icmp_seq=4 ttl=62
time=0.611 ms
64 bytes from palazzo.REDACTED.com (10.100.2.17): icmp_seq=5 ttl=62
time=0.890 ms
^C
--- palazzo.REDACTED.com ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4003ms
rtt min/avg/max/mdev = 0.572/0.645/0.890/0.126 ms
Can anyone shed light on this? My server config includes the following
line:
FPING="xymonping"
My xymon server is version 4.3.14.
Thanks,
Shawn
