Problems with DNS in Version 4.x

Hi all… i have upgraded to version 4.x (i already tested 4.2, 4.4, 4.5) and in all versions i have a problem in DNS, after a time working normal the dns stops, and in the dns config the primary and secondary ips revert to 0.0.0.0 and the “allow remote requests” is unchecked, i set the ips manually and check “allow remote requests” again, but does not work, mikrotik reverts all to 0.0.0.0 and uncheck the option… the dns only return to work after a reboot… after the reboot all options are ok, the primary and secondary ips are set correctly and the option “allow remo…” is checked, and all working normal for a time, after a variety time the simptoms occour again… exist some solution to this problem???

Thanks in advance, bye.

PS: In this moment i using version 4.2 (its the more stable dns version at this moment)

PS2: Sorry for the bad english.

Try “/ip dns print” from a terminal.

In this moment the dns is working normal, this is the print from " ip dns print" command:

primary-dns: xxx.xxx.xxx.40
secondary-dns: xxx.xxx.xxx.41
allow-remote-requests: yes
max-udp-packet-size: 512
cache-size: 24000KiB
cache-max-ttl: 1w
cache-used: 12079KiB

PS: I put XXX on Ips…

Thanks in advance…

Today I had the same problem with DNS
[admin@VPN_Serdi_Server] > ip dns print
primary-dns: 91.15.22.114
secondary-dns: 10.0.0.40
allow-remote-requests: yes
max-udp-packet-size: 512
cache-size: 24096KiB
cache-max-ttl: 1w
cache-used: 4105KiB

RouterOS v4.5

I had made support.rif when the problem was
support please see support.rif - dam man I cant add supout.rif
where can I send this supout.rif

sent it to support@mikrotik.com

I send a supout.rif to mikrotik in this e-mail… i waiting a return… thanks for all…

I too had problems with the MikroTik DNS server. I was just using it to cache records, as a resolving DNS server. After a couple days it would stop responding, so I stopped using it.

Same problem here… any solution ?

I have the same problem. Every three days I no longer walk and DNS report describes it as Nando_lavras.

I could not get solution to this problem, not updating to latest version it worked … the solution for me was to leave the Mikrotik DNS completely, I setup 2 servers with Ubuntu + bind9, set up the profiles of my PPPoE servers to new Ubuntu servers… problem solved, never had problems with it.

dikobraz23: Does this behavior continue as recent as ROS 4.9?

Normis et. al.: Has the MT crew identified the problem?

Nando_lavras: might you have a dhcp-client configured to use peer DNS?

This problem continue in 4.9… i not use dhcp-client, is a pppoe-concetrator… only used do authenticate pppoe users, the link is received with a static ip configuration (ethernet) and distributed with pppoe…

I am currently using a RB600a routerboard and a x86 RouterOS with ver 4.9 without any problem on DNS.

I too am using all types of RouterBoards, spanning multiple 3.x and 4.x releases, and have not had this problem with DNS. It occurred to me that DHCP could be changing the DNS settings, that’s all.

The problem I had in version 3.x. The problem is only on a quad Xeon server where it is connected to more than 1,000 users. Simply fails to Table of so many demands and time to go mental and tables where the same set DNS are 0.0.0.0.

Must be a problem of x86, I do not use Routerboards for servers, I use servers (Core 2 Duo with 2GB of RAM), but no more problem for me, the problem has been solved using the linux DNS servers.

Yes, there is small possibility, that problem could be on x86 routers. Anyone who is experiencing the problem with DNS in the same way, as Nando_lavras described in the first post, it would be great you can do small test.
Set the configuration to your router,
/system hardware set multi-cpu=no
/system reboot
Please post your report here or contact support (support@mikrotik.com), thank you very much for your help.

I use the option set-multi-cpu = no … and happens the same problem … with yes or no …

Yes this is the solution. But not for me. Ja mam to MK over 1000 clients over ip hotspot. To disable multi-cpu so cpu mam tapped to 100 percent.

dikobraz23 thank you then do not switch additional cores.

Nando_lavras,

  1. Have you rebooted the router after setting the configuration?
  2. How long you should wait to get the problem with DNS? How frequently it occurs?