DNS sensor details.

The DNS Sensor actually checks the DNS Server within your network, i.e. the one you got assigned via DHCP (or directly configured). May I ask what details you're interested in for these domains? Maybe we have an alternative Sensor that you could use :)

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Kind regards,
Stephan Linke, Tech Support Team

Yep. I have two Exchange EDGE servers, this sevrers are in DMZ network zone, PRTG server are in internal network. My task is to every minute request my internal DNS servers in internal network from this Exchange EDGE servers and check is this DNS server available and correctly resovle all my domains.

So now i make it by hands. I connect via RDP to two servers, open CMD-console, enter nslookup domain.domain.ru and check the answer. Then i enter next domain domain1.domain.com and check the answer. Sometime i see correct answer (IP list), sometime i have Request timeout and i understand that something goes wrong. If i have Request timeout as result of nslookup i have problem with mail routing.

So if say shortly: i need to get result of nslookup from remote server(s).

Thank you!

In this case, you'd need multiple DNS Sensors, indeed - one for every domain :)

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Kind regards,
Stephan Linke, Tech Support Team

As far as i understand all DNS sensors work only from Probe IP, or if i attach it to another device they will work as from remote host?

Well... depending on a few details what you want to accomplish - and which target servers - you can go pretty fancy with a PowerShell Script and a Custom EXE or Advanced Custom EXE sensor.

Have a look at those two possible commands:

• https://docs.microsoft.com/en-us/powershell/module/dnsserver/get-dnsserverresourcerecord?view=win10-ps
• https://docs.microsoft.com/en-us/powershell/module/dnsclient/resolve-dnsname?view=winserver2012r2-ps

In theory you could:

• check various DNS records at the same time
• check the same records against various DNS servers
  • internal DNS servers
  • external DNS servers like Google DNS or / and Open DNS
• compare even results of internal and external DNS responses - as long those aren't round-robin based (meaning you would get by default various IPs back)
• SFP / TXT records lookups and even theoretically investigating their results might be possible in theory
• etc.

There are ways - the question in the end is how far to you want to go and need to go.

What wonders me more is - why do you even need to check this stuff - what is the root cause of this request and on top of it in a one minute interval - the odds that those records even vanish are very low and Exchange is actually rather robust as well... I kinda wondered about it...

Regards

Florian Rossmark

www.it-admins.com

Quote from Vasiliy
As far as i understand all DNS sensors work only from Probe IP, or if i attach it to another device they will work as from remote host?

Actually, you'll need to add the Sensor to a real DNS server (i.e. a device that has the IP/FQDN of a DNS server within the network), as we're basically just doing some nslookup stuff :)

PRTG Scheduler | PRTGapi | Feature Requests | WMI Issues | SNMP Issues

Kind regards,
Stephan Linke, Tech Support Team