Does my office/lab server need to be providing these services?

I'm trying to figure out what services my university Ubuntu 22.04 computer needs to provide to other machines. I often ssh into this machine and other computers in my lab use it as an NFS server. I can't think of any other services the machine needs to provide, however. As a result, I'm trying to harden the computer by shutting down unnecessary services. Unfortunately given my knowledge of linux services and ports, I'm not sure which are necessary or not. If I run $ netstat -A inet --listening Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 0.0.0.0:37725 0.0.0.0:* LISTEN tcp 0 0 localhost:domain 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:sunrpc 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:nfs 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:8787 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:42757 0.0.0.0:* LISTEN tcp 0 0 localhost:51144 0.0.0.0:* LISTEN tcp 0 0 localhost:17603 0.0.0.0:* LISTEN tcp 0 0 localhost:17600 0.0.0.0:* LISTEN tcp 0 0 localhost:12546 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:56703 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:56607 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:db-lsp 0.0.0.0:* LISTEN tcp 0 0 localhost:44911 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:58017 0.0.0.0:* LISTEN tcp 0 0 localhost:ipp 0.0.0.0:* LISTEN tcp 0 0 localhost:32997 0.0.0.0:* LISTEN udp 0 0 0.0.0.0:17500 0.0.0.0:* udp 0 0 0.0.0.0:53815 0.0.0.0:* udp 0 0 0.0.0.0:55047 0.0.0.0:* udp 0 0 0.0.0.0:57529 0.0.0.0:* udp 0 0 localhost:domain 0.0.0.0:* udp 0 0 0.0.0.0:sunrpc 0.0.0.0:* udp 0 0 localhost:864 0.0.0.0:* udp 0 0 0.0.0.0:33798 0.0.0.0:* udp 0 0 0.0.0.0:35842 0.0.0.0:* udp 0 0 0.0.0.0:36165 0.0.0.0:* udp 0 0 0.0.0.0:mdns 0.0.0.0:* udp 0 0 0.0.0.0:40000 0.0.0.0:* udp 0 0 0.0.0.0:43526 0.0.0.0:* Because I was recently used to amplify a DNS attack, I've stopped the sunrpc service for the moment. My understanding is that I need that service as part of NFS (but my understanding could easily be wrong). 1) Based on my needs, which, if any of these services do I need to be providing to other machines. 2) Of those that I do need to provide, besides fail2ban for ssh connections, what steps do I need to take to harden my machine? This may be an overly broad or naive set of questions, if so any insight will still be greatly appreciated.