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vnshtc
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Static DNS records do work strange on Mikrotik

Sun Feb 19, 2023 6:51 pm

Hi everybody!

I've just faced with strange behavior of DNS resolver on my RB3011UiAS (ROS v7.7). At first glance, etherything works good, excepting static FQDN records stored in ip/dns/static. When I try to ping any of such records using Terminal, the name is resolved to an appropriate ip address as expected. BUT, as soon as I starting use Tools/Ping of the Winbox or Webfig GUIs, the error "Error in Ping To - Ip address expected!" occures. For me it looks very strange that the same (ping to) tool provides different results depending on what UI launches the tool, and I believe that the problem lies in some non-critical errors of the firmware resulted from one of the privious firmeware upgrade. However, before resetting, reflashing and reconfiguring the device, I would like to ask more experienced users for advice - am I missing something?

I would be very appreciated for any idea re this issue. Thank you in advance...

P.S. It seems that my router generally ignores its own static DNS entries (when I use Tools/Ping of the Winbox or Webfig GUIs, not Terminal), because an attempt to rewrite the ip address of any third-party resource, such as google.com, does not give the expected result - the domain name is simply resolved on the third-party dns servers in its native ip address.
 
Sob
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Re: Static DNS records do work strange on Mikrotik  [SOLVED]

Mon Feb 20, 2023 12:26 am

There's difference between DNS resolution:

- in Terminal it's done by router
- in WinBox it's done by machine it runs on
- I'm not sure about WebFig

Normally if machine with WinBox uses same router as its DNS resolver, there wouldn't be any difference. But depending on what static records you add, in 7.7 some should work, but some may not. Overriding records that exist in public DNS should be ok. But custom non-existing ones may break, because of bug (fixed in upcoming 7.8). If you add only A (IPv4), client can ask for AAAA (IPv6), which router forwards to upstream where it doesn't exist at all, and it will erroneously tell client that hostname doesn't exist at all.
 
vnshtc
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Re: Static DNS records do work strange on Mikrotik

Tue Feb 21, 2023 4:41 pm

Hellow Sob,

Thank you for the prompt reply and exhaustive description of the ROS/GUI DNS logic. This logic was quite unexpected for me, but it fully explains such a strange behavior of the Ping tool. I don't understand the reason for Mikrotik to implement such logic, but this feature will definitely have to be taken into account :-) One more thanks for your assistance and time.

With kindly regards,..

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