tcpdump by uid
 

is there a way to dump all the IP traffic from a given userid? i can do the dumping as root. i can give either the user name string or the user id number as appropriate.

the purpose is to collect all possible IP addresses a given website might be using. i want to route all traffic going to them to go through a specific VPN instead of the usual default.

the idea is to, at first, route everything through that VPN and access them only from that specific user (i will be logging in as that user instead of using sudo).

I would try to set a proxy for that user (if I understand well)

would a proxy also include web socket traffic (non-HTTP) that JavaScript does? in other words, do JavaScript apps connect to host names, IP addresses, or the server that the JavaScript came from?

that depends on the configuration and sometimes on the used app too, but in general yes.