[maqp]

"So while Signal's servers can see who to deliver the message to they cannot see who sent it."

Why can't they look at the TCP headers of incoming packets to determine source-IP? Also, why can't they look at session identifier or signal ID like phone number to determine who the sender is?

[voxic11]

I assume if you are trying to hide your communications you aren't connecting directly to signals servers, so IP should get you nothing. There is no session identifier or signalID attached to your message, its contained within the encrypted part of the message so only the receiver can determine who the message was sent by. https://signal.org/blog/sealed-sender/