Actually, ICMP echo-request and echo-reply packets are almost certainly not an issue here, nor is packet-filtering/firewalling. In current implementations, traceroute by default uses UDP packets to abitrary and unlikely-to-respond ports, varying the TTL and using the ICMP type 11 (Time Exceeded) from hops along the way to map the routing path.
The manpage in Fedora 8 says "We start our probes with a ttl of one and increase by one until we...got to the "host", or hit a max (which defaults to 30 hops)".
So, the behavior you're seeing is as documented. If a firewall were an issue in sending/receiving the packets used by traceroute, you'd see the 30-hop behavior whether the host was up or down.
On Mon, January 14, 2008 11:17, Michael A. Price wrote:
Josh,
Thanks for helping... The source/destination is on a closed network, sorry...and I don't own the router...
But, I don't understand, how the traceroute works when the host is up, but when the host is down it times out???
If it works when the host is up, then you would think the ACL on the router just before the host would allow my ICMP packets through.
What is your thoughts???
From: Josh Luthman [mailto:josh at imaginenetworksllc.com] Sent: Thursday, January 10, 2008 11:01 AM To: hobbit at hswn.dk Subject: Re: [hobbit] Re: Conn test problems
That third hop is denying ICMP echoes to you. Is it a router of your own or is it outside your network? If you'd be willing to share that destination with us at least I would be willing to traceroute it from my location to help see if it is an issue at your end or not.
On 1/10/08, Michael A. Price <mprice at sgt-inc.com> wrote:
Yes....
Its weird, from the shell#. I can trace route to the host if its up in 3 HOPS. But if the host is offline, it does 2 HOPS and then 28 more blank lines of stars. Not sure why it doesn't just time out after 3 HOPS, it takes a couple minutes to time out.
That's what my problem is, so I removed the trace option to my hosts. Any help would be great...
Thanks, michael
From: Josh Luthman [mailto:josh at imaginenetworksllc.com] Sent: Wednesday, January 09, 2008 3:32 PM To: hobbit at hswn.dk Subject: Re: [hobbit] Re: Conn test problems
Michael,
Were you the one that couldn't traceroute to the host via the shell?
Josh
On 1/9/08, Michael A. Price < mprice at sgt-inc.com <mailto:mprice at sgt-inc.com> > wrote:
My 'ping test completed' goes through the roof if my #trace tag is in the monitoring field and the host is down...
It keeps trying to trace route and it times out..
Never found a fix..
From: Josh Luthman [mailto: josh at imaginenetworksllc.com] Sent: Wednesday, January 09, 2008 10:55 AM To: hobbit at hswn.dk Subject: [hobbit] Re: Conn test problems
Has anyone else encountered issues like this? Has anyone else encountered any similar issues with all the conn tests going haywire?
I figured I'd also post this information while "bumping" the email:
bbgen for Hobbit version 4.2.0
Statistics:
Hosts : 164
Status messages : 531
Purple messages : 0
Pages : 1
TIME SPENT
Event Starttime Duration
Startup 1199894029.525853
Load links done 1199894029.526327 0.000474
Load bbhosts done 1199894029.531645 0.005318
ACK removal done 1199894029.531742 0.000097
Load STATE done 1199894029.563429 0.031687
Color calculation done 1199894029.563629 0.000200
Hobbit pagegen start 1199894029.563659 0.000030
Hobbit pagegen done 1199894029.573544 0.009885
BB2 generation done
1199894029.576605 0.003061
BBNK generation done 1199894029.577261 0.000656
Summary transmission done 1199894029.577265 0.000004
WML generation done 1199894029.578793 0.001528
Run completed 1199894029.578798 0.000005
TIME TOTAL 0.052945
bbtest-net version 4.2.0
SSL library : OpenSSL 0.9.8b 04 May 2006
LDAP library: OpenLDAP 20327
Statistics:
Hosts total : 161
Hosts with no tests : 1
Total test count : 181
Status messages : 182
Alert status msgs : 0
Transmissions : 3
DNS statistics:
hostnames resolved : 16
succesful : 16
failed : 0
calls to dnsresolve : 27
TCP test statistics:
TCP tests total : 13
HTTP tests : 5
Simple TCP tests : 8
Connection attempts : 13
bytes written : 780
bytes read : 22792
TIME SPENT
Event Starttime Duration
bbtest-net startup 1199893834.785076
Service definitions loaded 1199893834.787463 0.002387
Tests loaded 1199893834.793085 0.005622
DNS lookups completed 1199893834.883042 0.089957
Test engine setup completed 1199893834.886789 0.003747
TCP tests completed 1199893835.028904 0.142115
PING test completed (160 hosts) 1199893870.087696 35.058792
PING test results sent
1199893870.090125 0.002429
Test result collection completed 1199893870.090173 0.000048
LDAP test engine setup completed 1199893870.090175 0.000002
LDAP tests executed 1199893870.090177 0.000002
LDAP tests result collection completed 1199893870.090179 0.000002
NSLOOKUP tests executed 1199893870.244778 0.154599
Test results transmitted 1199893870.246478 0.001700
bbtest-net completed 1199893870.248556 0.002078
TIME TOTAL 35.463480
On 1/7/08, Josh Luthman <josh at imaginenetworksllc.com> wrote:
I've been getting a lot of these recently. A lot of the time I'll get a good 3/4 of the hosts I'm monitoring like this, other days it is just one or two. I can't seem to find any pattern to it. I'm very confident it isn't network related as it happens to the first entry, Hobbit server. I just can't imagine why it would have issues getting to 127.0.0.1!
I was also under the impression that the ping test is done every 60s or 120s so these tests just can't be true positive results.
Poking around I also found that the test to my hobbit server (this is 127.0.0.1 mind you) went up in early December.
Looking for any input at this point!
-- Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373
Those who don't understand UNIX are condemned to reinvent it, poorly. --- Henry Spencer
-- Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373
Those who don't understand UNIX are condemned to reinvent it, poorly. --- Henry Spencer
-- Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373
Those who don't understand UNIX are condemned to reinvent it, poorly. --- Henry Spencer
-- Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373
Those who don't understand UNIX are condemned to reinvent it, poorly. --- Henry Spencer