1847052 - matrix-client.matrix.org hasn't been DNS cached

Status: UNCONFIRMED

(Core :: Networking: DNS, defect, P3)

Description

[Tom [:tomacat]]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0

Steps to reproduce:

Log in Matrix with Element-Web (https://riot.im/app/),
Every minute have DNS request for matrix-client.matrix.org,
But I check out about:networking#dns, the expiration seconds are more than 1000.
Change network.dnsCacheExpiration to 3600, which can become more apparent.

I'm trying to reproduce it on another website, but failed. I don't know how to trigger this.

Expected results:

Firefox Should DNS cached for this domain.

Comment 1

[Tom [:tomacat]]

I thought it may HTTP OPTION request trigger DNS cache pass-by. Using following Javascript to request OPTIONS method, but don't see so many DNS requests like matrix-client.matrix.org:

var url = 'https://example.com/';
var xhr = new XMLHttpRequest();
xhr.open('OPTIONS', url, true);
xhr.send();

Comment 2

[Tom [:tomacat]]

But I resend the request on the Developer Tools, Every resend request cause a new DNS request.