My server was talking to the client. But so was something else .
There, nestled between legitimate ACK packets, was a series of RST (reset) packets with a TTL that didn’t match the rest of the stream. Someone—another student in the class, probably working on the offensive security track—had quietly ARP-poisoned my subnet. They weren't stealing data. They were just injecting resets to watch my retransmission timer explode.
CSC5113C does something crueler—and far more educational. It forces you to implement the protocols, then immediately break them. csc5113c
The first time you see a DNS exfiltration tunnel—where someone encoded /etc/passwd into subdomain requests—it feels like magic. By the end of the lab, you realize it’s just math. Clever, terrifying math.
I was debugging a "simple" TCP congestion control algorithm for my CSC5113C project. The assignment was straightforward: modify the Linux kernel’s TCP stack to improve throughput over high-latency links. Straightforward, until it wasn't. My server was talking to the client
Since course codes vary (e.g., University of Oklahoma’s CS/IT sequences), I have framed this around the spirit of an advanced, project-heavy networking/security course. By a Survivor of CSC5113C
Lab 4 is the turning point. You’re given a PCAP file—a recording of a real (anonymized) corporate network breach. Your job: reconstruct the attacker’s steps using only packet analysis. No logs. No alerts. Just 30,000 packets and your sanity. Someone—another student in the class, probably working on
Just don’t run your lab scripts on the university’s production VLAN. The network admin still sends the professor angry emails about "The Great Packet Heist of 2023." Final grade: A- (lost points for forgetting to close a raw socket). Worth it.
You learn fast. You learn that sequence numbers without crypto are just polite suggestions. You learn that "congestion" is often just malice. And you learn that tcpdump is the difference between an A and a sleepless incomplete. Ask any CSC5113C alumnus about ~/lab4/attacks/ . They’ll go quiet.