Re: [Tails-dev] TOR browser addon Adblock Plus vs. uBlock

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Auteur: Tobias Frei
Date:  
À: The Tails public development discussion list
CC: arrowscript
Sujet: Re: [Tails-dev] TOR browser addon Adblock Plus vs. uBlock
Hi L.R. D.S.,

Stating your opinion on a controversial topic and announcing to leave
the list in the same message feels like someone shouting their opinion
into a room full of people and slamming the door from the outside before
anyone can react. Also, doing so after someone pointed out to you why
your criticism was probably unjustified makes this behavior even more
sad, I'd say.

I'm sure nobody here thinks that criticism has to be perfect, and I also
don't think that - even after your first angry reaction - a calm,
objective explanation of the reasons for the criticized current behavior
is "dodging" at all.

About the PS, Tails already makes use of iptables to prevent (nearly)
any non-Tor traffic from happening. However, using a firewall to block
specific web pages will probably not work in the way you might expect it
to do - if there is the legitimate site
http://example.org/information, and the advertisement banner
http://example.org/advertisement.png, then you can't remove that banner
by denying access to the IP behind example.org. As far as I know, you
could, if the traffic is unencrypted (fails for Tor and even HTTPS
itself), use some special iptables rules to intercept all text and block
connections that contain what you're looking for. Add 1000 of these
rules, and network performance becomes horrible, I guess. DNS solutions
additionally fail whenever advertisement hosts are referenced using
their IP address instead of their hostname.
http://192.0.2.1/advertisement.png evades DNS solutions.

For Tails/Tor specifically, there's another huge problem with your
suggestion: DNS lookups are performed by the exit node, not your own
computer. Else, your DNS provider could easily see which hostnames you
look up, breaking anonymity. Connections in general are not made
directly to the web hosts, but instead to the Tor entry node, which
forwards your request. The only place to implement firewall/DNS
adblocking would be the exit node, not the computer running Tails. I'm
pretty sure you don't want the exit node operator to decide which hosts
you and all other Tor users are allowed to connect to. ;D

Without any "dodging" at all, I hope, this explains why neither firewall
nor DNS solutions can be "more effective and efficient" than a browser
addon for blocking advertisements on web pages. After all, use cases
like this one are what browser addons exist for.


Have a nice day, and feel free to come back whenever you want to. ^.^

Best regards,
Tobias Frei

[just yet another guest; not an official list admin statement or
whatever it might look like.]

Am 17.05.2015 um 01:42 schrieb L.R. D.S.:
>> basic guideline: Be excellent to each other.
>
> I do not agree with this. I should interpret better these 'sjw' guideline before
> enter here. By the way, I think you folks are using it to dodge the critic.
> If you think that a critic need to be "excellent" in all ways, then you'll never have
> a real critic here after all.
> I'll just remove myself from this list to evite more "non-excellent" mails.
>
>
> ps: A pf firewall or dns filtering would be more effective and efficient then a addon.
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