[dizhn]

We have a satellite office in Dubai. I know their static IP. When they connect to our imap/smtp server they are coming in from another IP. I never looked into it deeply but assumed their connection is being diverted for inspection. (If true, they would probably not be below performing industrial espionage with the data they are accessing)

[f4c39012]

I've debugged connection issues with someone in China. The same person, using the same browser and at the same time, showed up in the logs of two cloud apps with different IP addresses. The applications were adjacent in the cloud, same network config and everything. We figured there was always redirection, and we were never seeing their "true" IP address.

A simpler test is to search "what is my IP" and compare the values returned by different services.

[aeyes]

The IP space in China is wild, multiple ISPs use the same IP ranges and some even use foreign IP space but they don't route them outside of China. I wouldn't be at all surprised seeing proxy setups at ISPs trying to "fix" some of this.

Even when we had physical machines in Chinese data centers it didn't mean that our service was reachable from all ISPs. In 2010 we gave up on that and just started using Akamai China CDN with our servers in Europe.

[proto_lambda]

At that level, there is no reason to proxy it through a different IP address. If you control the network, you can just make the packets come from the original, real address.

[H8crilA]

It was probably written by junior devs, like most other software around the world.

[slt2021]

GFW that can inspect petabytes of traffic per second for 1.4 bln population cannot be written by juniors

[dizhn]

It might be something government mandated where all ISPs direct mail traffic to a central location. (The largest ISP is the government by the way)

[occamrazor]

Is the IMAP/SMTP connection not encrypted?

[philjohn]

Doesn't matter if the government mandates MITM and forces install of root certs on all clients.

[dizhn]

Yes they are encrypted.

[EGreg]

Speaking of satellites, the ones in geosynchronous orbit, how can Chinese block those?

[ec109685]

“We will shoot your satellite if you don’t block access while over China”.

[EGreg]

In orbit? Good luck

Lasers maybe?

[ImPostingOnHN]

the US has done so with a missile so basic that it's named "standard missile 3"

most satellites will just be following an uninterrupted, predictable path for most of their time