Tag the application type in a network packet

Question

Lets say I have a pcap capture that contains a mintue of Youtube video and a minute of a skype call. I also know exactly which packets belong to which application. Is there a way to tag a field in any of the headers of the packet to say that it belongs to a specific application.

Basically what I'm asking is that is there a way to tag a packet by adding additional information in a header field. At the same time I dont want to break any RFCs.

Thank you

Answer 1

As i understand you should have some kind of proxy that modifies tcp packet headers before passing it through.

there are some suggestions here:
How to write custom data to the TCP packet header options field with Java?
how to modify packet header(IP header, TCP Header) before the host send them into the network

you can also check this guide, it have section how to add extra headers info into packets:
http://grinder.sourceforge.net/g3/tcpproxy.html

is this applicable to your case?