A little bug...

RouterOS General
1

When I set rules from menu “DHCP-server”, it can make more than 2 DNS-servers shown in the picture 1. But when I make rules by the scripts and import from new-terminal,it’s prompting implied DNS-server should not have more than two DNS-servers, shown in the picture 2 and picture 3.

By my experiences, DNs-server has a very important position to a ethernet,so two DNS-servers are not enough, pls don’t make little concern of it.
1.jpg.jpg
2.jpg
3.jpg

2

confirming: v4.3 have the same bug

3

in 4.5 you will be able to add more than 2 DNS server entires in console.

4

by the way, what client can use more than two DNS? =) I saw MacOS yesterday - it uses only first two

5

do not know, but if you want to set more than 2 you can do that in CLI for whatever reason there is.

6

windows can use as many as you add.

7
  1. yes,I had said that in console it can be conducted more than two DNS, but I want automated import, so must be conducted by script.
  2. Almost every ISP provide two DNS, but it is far from enough, it did happen in my country just not long ago, the biggest ISP had broken down their four DNS simultaneously, owing to heavy traffic congestion, millions of people can’t get on net for two days,and it happened for over several times. So, I usually set up at least three DNS from two different ISP.
8

May I suggest that there may be a more thoughtful way of running with a simple 2 DNS solution.

If the purpose of multiple DNS is to create fall-over support should one fail, I would suggest that adding two DNS servers of the same ISP to be unwise, as everyone using that ISP will use the fall-over of the 2nd DNS for that ISP.

If ISP(a) has 2 DNS servers and server 1 crashes due to heavy workload then I suspect the 2nd will get all DNS requests from the first due to fall-over and similarly crash, perhaps in the meantime (until 4.5 comes out) set DNS 1 to be your main ISP DNS and set DNS2 to point to a second ISP or openDNS, given that openDNS is geared up to handle a significant amount of traffic, one or two sites more (no matter how big) probably won’t be a big strain for them (Unless openDNS is blocked from your ISP).

In 4.3, you can only have primary and secondary DNS entries http://wiki.mikrotik.com/wiki/File:Pppoe-dns-server.JPG, it seems that with the DHCP server option you can add more via winbox (I didn’t know that option existed!!!), but only for IP pools that are actively being served by your MT DHCP server. Sorry it doesn’t work in your code