nmap used with tcpreplay questions

Question

i am trying a SYN attack , in a controlled environment.

My process: I started tcpdump process with filters to capture packets from one PC to another, only outgoing packets , I started a nmap process with -sS , I captured the outgoing SYN packets into a pcap file.

Now I am using tcpreplay to send the pcap file with different --pps (packets per second) to see if I can detect anything on the receiving computer.

Question:

• By capturing the packets like this can I send them over and over again (lets say every hour , same pcap file) or do I have to capture every time? Do they have a lifespan? or a timestamp? (the nmap SYN outgoing packets)

Answer 1

I just tried it out and it seems like you can send them over and over again. They do have kind of a livespan (See TTL of IPv4 Packets: https://en.wikipedia.org/wiki/IPv4#TTL), not in terms of time, but in terms of how many hops they've been send trough, so this doesn't affect your question.