Is UDP traffic to port 53 blocked?

[bvkchaitanya]

Hi,


I am trying to learn setting up an authoritative DNS server in my homelab.

DNS resolution is working properly when I run DNS resolution over tcp (`dig +tcp test.domain.bvk.sh`), but doesn't work over UDP.

I have a Google Wifi device that acts as the router where I setup port-forwarding for both TCP/UDP traffic.

How can I get the DNS resolution work over UDP?


Thanks,
Chaitanya

[tony.b]

Hi there,
Thank you for reaching out, and I apologize that you are having these issues with the DNS resolution working over UDP. I confirmed with our team that the only port that we have blocked is 25, port 53 is open for all services, and that we are not blocking any UDP traffic through it. From our side there is nothing restricting service from getting to your equipment, I hope that you are able to find a setup solution within the devices to get them working.
Please do reach out if there are any other questions we can try and help with,
Tony Sonic Supervisor

[bvkchaitanya]

Hi,


Thanks for your response. My service uses Sonic Gigabit (though ATT fiber), so whom should I talk to for this UDP traffic issue?

Could you verify the DNS resolution with the two following commands from your network?

dig @99.130.253.220 +tcp test.domain.bvk.sh
dig @99.130.253.220 test.domain.bvk.sh

I would like to determine where the UDP traffic is being blocked.


Thanks,
Chaitanya

[tigertech]

While you're right that this works:

Code: Select all

dig @99.130.253.220 +tcp test.domain.bvk.sh

and this fails:

Code: Select all

dig @99.130.253.220 test.domain.bvk.sh

... this is nothing to do with Sonic. I tested it from three other unrelated networks (Amazon AWS, Hurricane Electric and Zayo) and the same thing happens with all of those.

There's presumably something wrong on the DNS server end.

[bvkchaitanya]

> There's presumably something wrong on the DNS server end.

I can resolve with both tcp and udp DNS resolution modes from within my local lan, so DNS server configuration seems correct.