Issue with using 1.1.1.1 as DNS

When I run a simple python program to fetch some data from any url, I get a delay of around 6 seconds. For example:

import requests

print(requests.get("http://example.com").text)

import requests

print(requests.get("http://example.com").text)

This seems to happen because it queries both the A and AAAA record at the same time and I only get a response for the A record (which was queried first). After not getting the AAAA record it asks for both of the records again but in succession. If I use the proxy of my router I don't have said issue. The first screenshot attached to the post is Wireshark with the filter set to frame contains "example" . If I specify for what type of TCPConnector to use e.g. with:

import aiohttp
import socket
import asyncio

async def fetch_data():
    connector = aiohttp.TCPConnector(family=socket.AF_INET6)
    async with aiohttp.ClientSession(connector=connector) as session:
        response = await session.get("https://www.example.com")
        return await response.text()


data = asyncio.run(fetch_data())
print(data)

import aiohttp
import socket
import asyncio

async def fetch_data():
    connector = aiohttp.TCPConnector(family=socket.AF_INET6)
    async with aiohttp.ClientSession(connector=connector) as session:
        response = await session.get("https://www.example.com")
        return await response.text()


data = asyncio.run(fetch_data())
print(data)

It only asks for the AAAA record and I don't get any delay. The second Screenshot is when I've used my router as my DNS. Another important thing to add is that I am using archlinux on kernel version 6.6.8.arch1-1. It would be nice to know if this is an issue caused by me which I am able to resolve by myself, if this is expected behaviour or an issue with the cloudflare DNS. Thank you!

2 Replies

Erisa•11mo ago

I suspect you already tried but does the same thing happen with e.g. 8.8.8.8?

phiwijoOP•11mo ago

yep It only happens when the socket family is set to AF_UNSPEC (which is the default) I wrote basically the same in C++ and I get the same issue as in python if you use AF_UNSPECC as the socket family (which makes sense).

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Issue with using 1.1.1.1 as DNS