how do i see all ports scanned from my nmap scan

To start, if you're seeing that many ports are filtered at the same time, likely, your networking setup isn't working. I'd also run a ping and use tools like ping.pe for how other servers are connecting to your Linode. I've included some additional troubleshooting resources towards the end of my response.

Now, regarding your specific question: when it comes to nmap scans, unless ports are specified, it will scan the most common 1,000 ports for each protocol. This comes from their documentation:

Port Specification and Scan Order

That page from their documentation also shows how you can specify specific ports. If you know which ports the services that you're checking on run on, you can check the service and port:

nmap -sV $ipaddress -p 22,80,443,3306 --reason

That command will check the service (-sV) on ports (-p) 22, 80, 443, and 3306, and will provide a little more detail (--reason).

We have a great Troubleshooting Basic Connection Issues guide. I'd also check to see if you have Network Helper enabled. In many cases, this will help resolve any issues with bringing up networking interfaces on Linodes. You can also use Lish (Linode Shell) to check on the Linode itself.