These terminals are not in DNS. There's also a large amount of Cisco accesspoints that are fpinged the same way. These AP's are also not in DNS. The number of AP's is even larger than the number of terminals: 247.

-----Oorspronkelijk bericht----- Van: Hubbard, Greg L [mailto:greg.hubbard at eds.com] Verzonden: vrijdag 2 november 2007 15:21 Aan: hobbit at hswn.dk Onderwerp: RE: [hobbit] strange result in fping by hobbit and fping by yours truly

DNS?

-----Original Message----- From: Dennis Ortsen [mailto:dortsen at gmail.com] Sent: Friday, November 02, 2007 7:47 AM To: hobbit at hswn.dk Subject: [hobbit] strange result in fping by hobbit and fping by yours truly

Hi everyone,

I've got a somewhat strange issue with fping in hobbit.

I've got a list of about 122 terminals that are used for a chipcard payment system. Each one of them has an ip-address and connects to a server to process the payments. Every now and then the terminals loose the connection or whatever, they need to be reset before they can process the payments again on the server. I thought I might use Hobbit to ping all the terminals to see if they still respond to a ping. If they don't reply anymore, they need a reset.

I only do a conn test on an ip-address. I use the full path to fping in hobbitserver.cfg, without any extra parameters. When hobbit starts testing the connection, only 14 terminals respond to a ping, but when I execute a fping myself (as the hobbit user) in a shell to the same amount of terminals, I get a totally different result, instead of 14 responding terminals, I get 95 responding terminals with fping! It's not just a lucky shot, I can keep on trying these terminals, the huge difference remains whether I fping them myself or when hobbit fpings them.

I'm running hobbit 4.2.0. According to bbtest I have 806 hosts that are pinged, that takes about 26 seconds to complete. To complete all tests (954), it takes about 47 seconds.

Does anyone have a clue why specifically these terminals have such a difference in hobbit ping and a ping performed by myself?

I can't explain it, and it doesn't seem like a timeout (latency) issue to me either.

Thanks in advance,

Br.

Dennis

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What was suggested was that you have something like

172.16.1.50 terminal150.notmydomain.com #

Here Hobbit is attempting to resolve terminal150.notmydomain.com, fails, and then pings the IP address. Since you know the IP and it isn't going to change, try

172.16.1.50 terminal150.notmydomain.com # testip

See if that resolves your issue. Note you can click on the host on the web interface and it will say the IP it is pinging.

On 11/2/07, Hobbit User <hobbit at epperson.homelinux.net> wrote:

You're aware, aren't you, that unless you have "testip" keyword on the bb-hosts line, hobbit DNS resolves the bb-hosts name and uses the bb-hosts IP only if the name lookup fails?

On Fri, November 2, 2007 11:28, Dennis Ortsen wrote:

...

These terminals are not in DNS. There's also a large amount of Cisco accesspoints that are fpinged the same way. These AP's are also not in DNS. The number of AP's is even larger than the number of terminals: 247.

...

-----Oorspronkelijk bericht----- Van: Hubbard, Greg L [mailto:greg.hubbard at eds.com] Verzonden: vrijdag 2 november 2007 15:21 Aan: hobbit at hswn.dk Onderwerp: RE: [hobbit] strange result in fping by hobbit and fping by yours truly

DNS?

-----Original Message----- From: Dennis Ortsen [mailto:dortsen at gmail.com] Sent: Friday, November 02, 2007 7:47 AM To: hobbit at hswn.dk Subject: [hobbit] strange result in fping by hobbit and fping by yours truly

Hi everyone,

I've got a somewhat strange issue with fping in hobbit.

I've got a list of about 122 terminals that are used for a chipcard payment system. Each one of them has an ip-address and connects to a server to process the payments. Every now and then the terminals loose the connection or whatever, they need to be reset before they can process the payments again on the server. I thought I might use Hobbit to ping all the terminals to see if they still respond to a ping. If they don't reply anymore, they need a reset.

I only do a conn test on an ip-address. I use the full path to fping in hobbitserver.cfg, without any extra parameters. When hobbit starts testing the connection, only 14 terminals respond to a ping, but when I execute a fping myself (as the hobbit user) in a shell to the same amount of terminals, I get a totally different result, instead of 14 responding terminals, I get 95 responding terminals with fping! It's not just a lucky shot, I can keep on trying these terminals, the huge difference remains whether I fping them myself or when hobbit fpings them.

I'm running hobbit 4.2.0. According to bbtest I have 806 hosts that are pinged, that takes about 26 seconds to complete. To complete all tests (954), it takes about 47 seconds.

Does anyone have a clue why specifically these terminals have such a difference in hobbit ping and a ping performed by myself?

I can't explain it, and it doesn't seem like a timeout (latency) issue to me either.

Thanks in advance,

Br.

Dennis

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-- 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

The testping tag solved my problem.

Strange however that with that large number of access points I didn't have the same issue. Perhaps it's just the additional number of IP-addresses that are not resolvable that made this visible?

Anyway, I now get the correct results, thanks guys.

Br.

Dennis

-----Oorspronkelijk bericht----- Van: Henrik Stoerner [mailto:henrik at hswn.dk] Verzonden: vrijdag 2 november 2007 18:07 Aan: hobbit at hswn.dk Onderwerp: Re: [hobbit] strange result in fping by hobbit and fping by yourstruly

On Fri, Nov 02, 2007 at 01:46:44PM +0100, Dennis Ortsen wrote:

...

I only do a conn test on an ip-address. I use the full path to fping in hobbitserver.cfg, without any extra parameters. When hobbit starts testing the connection, only 14 terminals respond to a ping, but when I execute a fping myself (as the hobbit user) in a shell to the same amount of terminals, I get a totally different result, instead of 14 responding terminals, I get 95 responding terminals with fping! It's not just a lucky shot, I can keep on trying these terminals, the huge difference remains whether I fping them myself or when hobbit fpings them.

I'm running hobbit 4.2.0. According to bbtest I have 806 hosts that are pinged, that takes about 26 seconds to complete. To complete all tests (954), it takes about 47 seconds.

Does anyone have a clue why specifically these terminals have such a difference in hobbit ping and a ping performed by myself?

What error does the failed ping tests show - DNS error, or just ping failure ? If it's DNS errors, use the "testip" tag to avoid doing DNS lookups - I understand from the other mails in the thread that these systems are not in the DNS.

I suspect it might be an issue with the number of tests running simultaneously. ICMP packets have lower priority in most network equipment, and is therefore the first packets to be discarded when there is a lot of traffic on the network. Since you're referring to "terminals" they might not have a lot of memory for network buffers and therefore they might drop packets more often than "real" computers.

There is also a possibility that the number of hosts tested is overflowing the ARP cache table on the Hobbit server, which can lead to packets being lost.

I'd suggest starting with some extra options for bbtest-net (in hobbitlaunch.cfg): Add --concurrency=32 to the bbtest-net command, and change the FPING setting in hobbitserver.cfg to FPING="fping -i150", this will increase the time fping waits between sending packets from 25 ms to 150 ms, so there is less ICMP traffic on the network.

You can replicate how Hobbit performs the ping test by putting the IP's of all your hosts into a text file (one IP per line), then run fping -Ae </tmp/IPlist.txt

Regards, Henrik

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