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GoodbyeDPI: Deep Packet Inspection circumvention utility

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Re: GoodbyeDPI: Deep Packet Inspection circumvention utility

#51
post #33

Looking at the circumvention techniques GoodbyeDPI uses makes me want to cry. Is this really the state of DPI in 2022: changing Host to hoSt, or adding white spaces between method and URI actually works?

It is harder problem that it sounds. Deep packet inspection needs to happen at some linespeed. More work you do the harder it is to process it all fast enough. You can write stuff for single packets, but when you have lot of connections happening it becomes much harder problem.

Re: GoodbyeDPI: Deep Packet Inspection circumvention utility

#52
post #33

Looking at the circumvention techniques GoodbyeDPI uses makes me want to cry. Is this really the state of DPI in 2022: changing Host to hoSt, or adding white spaces between method and URI actually works?

I suspect it is also due to the scale at which DPI is used; every additional bit of complexity quickly adds up to increase the amount of processing power required.

Re: GoodbyeDPI: Deep Packet Inspection circumvention utility

#53

Earlier quoted context omitted.

Well, the good point of GoodbyeDPI is exactly so that it preserves your IP address. Normally, when trying to circumvent censorship, you would need a VPN server in a different country. But the downsides are that the bank will deny all transactions and call you (OK, answered, they added the VPN IP to the whitelist), that you will miss local-only content, you won't be able to register for a doctor appointment online (th…

I wonder why a VPN is the default solution (with all complications it ensues, some of which you've listed), when a simple SSH tunnel to any server in a sane location does just fine. `ssh server -D12345`, point your applications to socks5 at localhost:12345, and it's done. It's dead simple to only allow/deny those sites that you (don't) need to go through another server, and the traffic is encrypted (and optionally co…

It's easier to detect that someone is using a SOCKS tunnel – from memory, one way it might be exposed is if the packet TTL is incongruous [1] as I don't think SOCKS rewrites those.

At the height of the pandemic I travelled to Denmark for work (on a clinical trial) and had a UK negative covid test to report to the UK government that I hadn't got around to – whose website geo-blocks people reporting covid tests from outside a UK IP address (even if, e.g. you'd just left it and wanted to report a negative test taken the day before). A SOCKS proxy was detected and I got a "we cannot verify you are in the UK" message. A wireguard VPN worked fine.

[1] https://incolumitas.com/2021/03/13/tcp-ip-fingerprinting-for...

Re: GoodbyeDPI: Deep Packet Inspection circumvention utility

#54
post #6

Haha that’s cute. Here in china the GFW now simply routes the IPs to blackhole. False positive by virtual host or CDN you ask? They don’t care :)

That's what domain fronting is for, and even though the GFW attempts to filter by SNI, genetic algorithms like Geneva are able to find workarounds: https://geneva.cs.umd.edu/papers/foci21.pdf

IP Fronting too: https://research.cloudflare.com/publications/Fayed2021/

Re: GoodbyeDPI: Deep Packet Inspection circumvention utility

#55

Looks like it uses WinDivert as the filtering driver, which says on its site that "Windows Server 2016 systems must have secure boot disabled"; not entirely surprising and a reminder of what a lot of the "security" stuff is really securing.

Censorship bypass needn't necessarily be a security solution.

Re: GoodbyeDPI: Deep Packet Inspection circumvention utility

#56
post #14

Looks like it uses WinDivert as the filtering driver, which says on its site that "Windows Server 2016 systems must have secure boot disabled"; not entirely surprising and a reminder of what a lot of the "security" stuff is really securing.

"secure boot must be disabled" is the equivalent of "in case of permissions error, just chmod 777". secure boot literally protects the user first, and is configurable with user provided keys on the vast vast majority of open platform computers (i.e. amd64) "prevent injection of a driver that can divert all my shit at the kernel level" is exactly what you want secure boot protecting you from. there is no limitation of…

"prevent injection of a driver that can divert all my shit at the kernel level" is exactly what you want secure boot protecting you from.

The only thing Secure Boot is doing here is preventing you from loading a driver not blessed by Microsoft. They would happily bless "a driver that can divert all my shit at the kernel level", but it costs too much for the maintainer of WinDivert.

Re: GoodbyeDPI: Deep Packet Inspection circumvention utility

#58
post #57

Sorry, might be a dumb question, but isn't this simply a matter of encrypting your packets or using a VPN?

You certainly can pass all blocked traffic through VPN. But this is a cheaper (and because of that is more scalable) way to pass through.

Re: GoodbyeDPI: Deep Packet Inspection circumvention utility

#59

Earlier quoted context omitted.

Well, the good point of GoodbyeDPI is exactly so that it preserves your IP address. Normally, when trying to circumvent censorship, you would need a VPN server in a different country. But the downsides are that the bank will deny all transactions and call you (OK, answered, they added the VPN IP to the whitelist), that you will miss local-only content, you won't be able to register for a doctor appointment online (th…

I wonder why a VPN is the default solution (with all complications it ensues, some of which you've listed), when a simple SSH tunnel to any server in a sane location does just fine. `ssh server -D12345`, point your applications to socks5 at localhost:12345, and it's done. It's dead simple to only allow/deny those sites that you (don't) need to go through another server, and the traffic is encrypted (and optionally co…

Encapsulating TCP in TCP results in exponential backoff and retransmissions in the event of loss.
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