Let me tell you a funny story that will show you the importance of TTL when sending packages. 

Back in the day, in 1971, there was a programmer called Bob Thomas who was working on mainframe computers. He got bored and decided to play around. After a while, Bob created a small software called the Creeper and released it on the network. It was a tiny code with the message ā€œIā€™m the creeper: catch me if you canā€. Ray Tomlinson, a colleague of his, added the functionality and allowed the code to copy itself. This was the first computer virus. The virus was unstoppable because there was no antivirus at this time, and it had no TTL, so it could go around the network forever. The co-creator Ray needed to invent the first antivirus to stop it. Otherwise, it could still go around for a long time. 

So what is TTL in networking?