[smokeping-users] DHCP handling

[Joshua Cameron]

Great explanation, thanks! Good to know about the DNS resolver steps. Will keep that in mind.

Interesting idea.

One last question, hope this one doesn't sound too strange.
How would I go about disabling checks on a device? But keeping the graph.

If I have a radio called "Mt Gibraltar Southwest" and change it to "Mt Gibraltar North" say if it gets repurposed.

I'd love to be able to go check the history data from its old name, but I don't want it to keep checking it(Since I'll be using MAC.tld.com.au, it'd still reply).
Would removing the host line from the config file simply disable checks? But allow me to go back and see the old graph?

Thanks again,
Joshua

From: Douglas Spindler [mailto:doug.spindler at gmail.com]
Sent: Monday, April 11, 2016 9:57 AM
To: Joshua Cameron; smokeping-users at lists.oetiker.ch
Subject: RE: [smokeping-users] DHCP handling

Great question.   The DNS resolver checks to see if it  the named being queried is its own, then the local Host file first, cache, and then a DNS query.

I'm wondering if you could also use a secondary or tertiary DNS entry which would only be in your smkokeping host.  (This way you could run multiple smokeping hosts and only have to run one script.  The on this DNS server host run the script to populate the DNS table.

Let us know how it works out for you.



From: smokeping-users [mailto:smokeping-users-bounces+doug.spindler=gmail.com at lists.oetiker.ch] On Behalf Of Joshua Cameron
Sent: Sunday, April 10, 2016 4:36 PM
To: smokeping-users at lists.oetiker.ch<mailto:smokeping-users at lists.oetiker.ch>
Subject: Re: [smokeping-users] DHCP handling

Sorry, I mean whenever a device is added or removed from the network I'll have to have the script re-write the config file then restart the service.
Is that going to cause any issues on Smokeping side? Restarting every couple days? I don't think that it would but thought I'd ask.

From: smokeping-users [mailto:smokeping-users-bounces+joshuac=ace.com.au at lists.oetiker.ch] On Behalf Of Joshua Cameron
Sent: Monday, April 11, 2016 9:33 AM
To: smokeping-users at lists.oetiker.ch<mailto:smokeping-users at lists.oetiker.ch>
Subject: Re: [smokeping-users] DHCP handling

Douglas,

Script to work with the host file sounds great.
Did a few tests with that idea and it looks like it'll work.
Much appreciated.

When the host is passed into FPing, will it check the hostfile everytime it's run or will it cache the DNS requests?
Would I have to flush DNS cache whenever I change host file if something changes IP?

Whenever something changes IP address, I'll have to have the script re-write the config file for Smokeping then restart the service.
Is that going to cause any issues on Smokeping side?

I'm just going to do this with my host file:
IPADDRESS MAC.tld.com.au
Then put the MAC.tld.com.au as the host in the Smokeping config file.

Joshua Cameron
Systems Administrator

From: Douglas Spindler [mailto:doug.spindler at gmail.com]
Sent: Monday, April 11, 2016 9:02 AM
To: Joshua Cameron; smokeping-users at lists.oetiker.ch<mailto:smokeping-users at lists.oetiker.ch>
Subject: RE: [smokeping-users] DHCP handling

BOOTP?  Or use a script to populate the  host file.

From: smokeping-users [mailto:smokeping-users-bounces+doug.spindler=gmail.com at lists.oetiker.ch] On Behalf Of Joshua Cameron
Sent: Sunday, April 10, 2016 3:56 PM
To: smokeping-users at lists.oetiker.ch<mailto:smokeping-users at lists.oetiker.ch>
Subject: [smokeping-users] DHCP handling

Hey,

I use Smokeping for about 40 devices at the moment, but we've got around 200 more on the network I'd like to add to it.

However some of the devices I want to monitor on our network can have dynamic IP addresses(DHCP), beside setting everything to static IPs which is never gonna happen, is there a way to keep the ping history data in Smokeping associated to a device across IP address changes?
Some sort of MAC address lookup or similar?

Joshua Cameron
Systems Administrator
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