Csc5113c

There is a moment in every Computer Science graduate course where the textbook stops making sense and reality kicks in. For me, that moment came at 2:00 AM in the networking lab, watching Wireshark scroll by like the green code from The Matrix .

One student famously found a delayed SQL injection spread across 47 fragmented ICMP echo requests. The professor didn’t even know that was possible until the student presented it. "Don't trust the wire. Don't trust the endpoint. Don't trust your textbook." This isn't paranoia. It’s the course’s core thesis. The Internet was built on trust. Modern networks survive on verification. csc5113c

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. There is a moment in every Computer Science

My server was talking to the client. But so was something else . The professor didn’t even know that was possible

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.

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.

CSC5113C won’t just teach you how networks work. It will teach you how they fail . And in doing so, it will make you one of the rare engineers who can actually defend them.