Re: Speaking of DNS server software...

[Ryan Hamel via NANOG <nanog () lists nanog org>]

Not only is there struct, but also scapy which can craft any packet with ease. A quick Google search shows DNS 
examples, https://thepacketgeek.com/scapy/building-network-tools/part-09/.

Combining asyncio with uvloop also provides very good performance.

Ryan Hamel

________________________________
From: John Levine via NANOG <nanog () lists nanog org>
Sent: Sunday, August 10, 2025 5:56 PM
To: nanog () lists nanog org <nanog () lists nanog org>
Cc: John Levine <johnl () iecc com>
Subject: Re: Speaking of DNS server software...

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It appears that William Herrin via NANOG <nanog () lists nanog org> said:
> Python doesn't work this way. Its memory management is abstracted away
> from the programmer and the programmer does not control its precise
> structure. For Python to access a DNS packet, the programmer must pack
> and unpack an array of bytes using complex software of their own
> devising. You can't just tell Python, "This is the complex data
> structure these bytes contain, let me access the data without
> unpacking it."

The python struct module is pretty fast, since it's written in C.

I recently rewrote the abuse.net DNS server in python doing
white lies on the fly DNSSEC signing.  It's fast enough.

R's,
John
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