20
What does network.http.http3.sni-slicing do in Firefox? (programming.dev)
submitted 2 weeks ago by ariadna@programming.dev to c/firefox@lemmy.ml
3 comments fedilink hide all child comments

Hi everyone,

I came across the Firefox preference network.http.http3.sni-slicing, which appears to be related to HTTP/3 and SNI handling. However, I’ve found very little documentation explaining what it actually does.

Could someone with knowledge of Firefox internals or HTTP/3 clarify:

  • What exactly does this setting change in the browser’s behavior?
  • Does it provide any privacy or security benefits?

I’d appreciate any insights. Thanks!

you are viewing a single comment's thread
view the rest of the comments
[-] ariadna@programming.dev 4 points 2 weeks ago

@mouse@midwest.social, @ferric_carcinization@lemmy.ml, thank you for the help and the links — things are a bit clearer now.

As I understand it, SNI slicing helps obscure the presence of the SNI field in the TLS ClientHello by splitting it into two chunks. The idea, it seems, is to make it more difficult for third-party network filters or DPI systems to detect or extract the SNI reliably.

this post was submitted on 24 Jul 2025
20 points (95.5% liked)

Firefox

20639 readers
214 users here now

/c/firefox

A place to discuss the news and latest developments on the open-source browser Firefox.

Rules

1. Adhere to the instance rules

2. Be kind to one another

3. Communicate in a civil manner

Reporting

If you would like to bring an issue to the moderators attention, please use the "Create Report" feature on the offending comment or post and it will be reviewed as time allows.

founded 5 years ago
MODERATORS
k_o_t@lemmy.ml
golden_zealot@lemmy.ml