how to proxy dns with tcp only

RouterOS General
1

can routeros do this?

2

RouterOS DNS cache works with both - UDP and TCP. However, UDP is preferred due to nature of DNS. To force TCP you have to block UDP (that is kind of pointless)

3

i tried,not work…
test with nslookup,it just show me:

time out!!!

it’s only use udp.

4

by default dns cache use UDP and TCP port #53

if you are using nslookup, you can do the following (at least for linux)

$ nslookup
> set vc
> server <your dns cache>
> mikrotik.com

if you want to make sure that request is done over tcp, you can use packet sniffer on your host (like wireshark, or packet nisffer on your router)

5

use [nslookup google.com (mikrotik dns proxy)]
and still get timed out!

so,mikrotik dns proxy use udp only

6

I’d suggest to have a look at DNS protocol details.
Standard queries always use UDP, TCP is only used for responses exceeding 512 bytes.
Even though it is stated that some DNS also support TCP, it is not given that the querying system uses tcp as well.

So it’s not a bug - it’s by design.
-Chris