Other machines were not able to connect to my laptop, either through scp or ssh.
The service called nifd which 'is a daemon which runs on Howl clients to monitor the state of a network interace. nifd must be running on systems that use autoidp and mDNSResponder to automatically obtain a Link-Local IPv4 address and do Zeroconf service discovery. nifd should not be running otherwise.'
Now whatever that means. The last sentence was vital. That service needed to be stopped. I stopped it. And the scp started working.
Bits of Learning
Learning sometimes happens in big jumps, but mostly in little tiny steps. I share my baby steps of learning here, mostly on topics around programming, programming languages, software engineering, and computing in general. But occasionally, even on other disciplines of engineering or even science. I mostly learn through examples and doing. And this place is a logbook of my experiences in learning something. You may find several things interesting here: little cute snippets of (hopefully useful) code, a bit of backing theory, and a lot of gyan on how learning can be so much fun.