Hi there,

I upgrade Debian for the ROC-RK3328-CC into Devuan but I feel I missed some important network packages, since, personally, the Debian image provided by Libre.Computer was very opinionated.

On my Devuan desktop installation I have these packages installed:

$ aptitude search '~i ~d network'
i A avahi-autoipd                   - Avahi IPv4LL network address configuration
i A avahi-daemon                    - Avahi mDNS/DNS-SD daemon                  
i A avahi-utils                     - Avahi browsing, publishing and discovery u
i A dbus-system-bus-common          - simple interprocess messaging system (syst
i A dirmngr                         - GNU privacy guard - network certificate ma
i A gir1.2-nm-1.0                   - GObject introspection data for the libnm l
i A glib-networking                 - network-related giomodules for GLib       
i A glib-networking-common          - network-related giomodules for GLib - data
i A glib-networking-services        - network-related giomodules for GLib - D-Bu
i A iftop                           - displays bandwidth usage information on an
i   ifupdown                        - high level tools to configure network inte
i   iproute2                        - networking and traffic control tools      
i   iputils-ping                    - Tools to test the reachability of network 
i A libaudio2                       - Network Audio System - shared libraries   
i A libavahi-client3                - Avahi client library                      
i A libavahi-common-data            - Avahi common data files                   
i A libavahi-common3                - Avahi common library                      
i A libavahi-core7                  - Avahi's embeddable mDNS/DNS-SD library    
i A libavahi-glib1                  - Avahi GLib integration library            
i A libmng1                         - Multiple-image Network Graphics library   
i A libnet-netmask-perl             - module to parse, manipulate and lookup IP 
i A libnm0                          - GObject-based client library for NetworkMa
i A libnma-common                   - NetworkManager GUI library - translations 
i A libnma0                         - NetworkManager GUI library                
i A libnss3                         - Network Security Service libraries        
i A libqt5network5                  - Qt 5 network module                       
i A libsnmp40                       - SNMP (Simple Network Management Protocol) 
i A libsodium23                     - Network communication, cryptography and si
i   libuuid1                        - Universally Unique ID library             
i   net-tools                       - NET-3 networking toolkit                  
i   netbase                         - Basic TCP/IP networking system            
i A network-manager                 - network management framework (daemon and u
i A network-manager-gnome           - network management framework (GNOME fronte
i   pngquant                        - PNG (Portable Network Graphics) image opti
i   rfkill                          - tool for enabling and disabling wireless d
i   tigervnc-viewer                 - Virtual network computing client for X    
i   traceroute                      - Traces the route taken by packets over an 
i A xfce4-netload-plugin            - network load monitor plugin for the Xfce4 
$ aptitude search '~i ~d dhcp'
i A avahi-autoipd                   - Avahi IPv4LL network address configuration
i A dnsmasq-base                    - Small caching DNS proxy and DHCP/TFTP serv
i   isc-dhcp-client                 - DHCP client for automatically obtaining an
i   isc-dhcp-common                 - common manpages relevant to all of the isc

But which are the mandatory ones?

Thanks 🙏

If you're using DHCP, "isc-dchp"-packages are necessary i think. I would keep net-tools, netbase, iproute2 and ifupdown also. Traceroute for debugging purposes.

Ok, removal of libavahi-packages may have unwanted side-effect so better to keep them for now.
The other ones are not so "mandatory". If you're using gpg for something, dirmngr may be necessary.

If you know how to edit files under /etc/network , network-manager-* packages are pointless.
And if you need to connect to other computers with vnc, tigervnc is necessary, otherwise not.

if I don't block IPv6 I can't get an IPv4 address to ssh into the SBC, and I wonder which packages I might have missing.

The only thing you really "need" for a static-ip ethernet connection is a working NIC driver and ifconfig or ip (from net-tools and iproute2 respectively).
When you say "get an IP" I assume you mean over DHCP? If so, I suggest trying with a hand-configured or ifupdown managed static IP (i.e. dump networkmanagermangler) first, then moving on to manually invoking whatever DHCP client you're using with some appropriate --verbose or --debug flags to see what's going on.

Frankly, other than for laptops or tablets that move between wireless networks constantly (and even then only if you must have a shiny GUI) I find networkmangler more aggravation than it's worth. IME ditching it is step one in any network troubleshooting.

Are relevant only for wireless connections, and the former only for WPA encrypted wireless connections specifically.

Mandatory?

You were right... What I would say was "essentials" or "recommended"; so basically if I don't block IPv6 I can't get an IPv4 address to ssh into the SBC, and I wonder which packages I might have missing.

which are the mandatory ones?

Mandatory? This is GNU/Linux we're talking about here, there is no "mandatory" beyond a kernel, init and shell.
That said you'll almost certainly want net-tools, netbase and ifupdown. Probably a dhcp client of some kind as well.
The rest is up for debate, and heavily influenced by your choice of desktop and the services you intend to run and/or connect to.

I upgrade Debian for the ROC-RK3328-CC into Devuan but I feel I missed some important network packages, since, personally, the Debian image provided by Libre.Computer was very opinionated.

On my Devuan desktop installation I have these packages installed:

$ aptitude search '~i ~d network'
i A avahi-autoipd                   - Avahi IPv4LL network address configuration
i A avahi-daemon                    - Avahi mDNS/DNS-SD daemon                  
i A avahi-utils                     - Avahi browsing, publishing and discovery u
i A dbus-system-bus-common          - simple interprocess messaging system (syst
i A dirmngr                         - GNU privacy guard - network certificate ma
i A gir1.2-nm-1.0                   - GObject introspection data for the libnm l
i A glib-networking                 - network-related giomodules for GLib       
i A glib-networking-common          - network-related giomodules for GLib - data
i A glib-networking-services        - network-related giomodules for GLib - D-Bu
i A iftop                           - displays bandwidth usage information on an
i   ifupdown                        - high level tools to configure network inte
i   iproute2                        - networking and traffic control tools      
i   iputils-ping                    - Tools to test the reachability of network 
i A libaudio2                       - Network Audio System - shared libraries   
i A libavahi-client3                - Avahi client library                      
i A libavahi-common-data            - Avahi common data files                   
i A libavahi-common3                - Avahi common library                      
i A libavahi-core7                  - Avahi's embeddable mDNS/DNS-SD library    
i A libavahi-glib1                  - Avahi GLib integration library            
i A libmng1                         - Multiple-image Network Graphics library   
i A libnet-netmask-perl             - module to parse, manipulate and lookup IP 
i A libnm0                          - GObject-based client library for NetworkMa
i A libnma-common                   - NetworkManager GUI library - translations 
i A libnma0                         - NetworkManager GUI library                
i A libnss3                         - Network Security Service libraries        
i A libqt5network5                  - Qt 5 network module                       
i A libsnmp40                       - SNMP (Simple Network Management Protocol) 
i A libsodium23                     - Network communication, cryptography and si
i   libuuid1                        - Universally Unique ID library             
i   net-tools                       - NET-3 networking toolkit                  
i   netbase                         - Basic TCP/IP networking system            
i A network-manager                 - network management framework (daemon and u
i A network-manager-gnome           - network management framework (GNOME fronte
i   pngquant                        - PNG (Portable Network Graphics) image opti
i   rfkill                          - tool for enabling and disabling wireless d
i   tigervnc-viewer                 - Virtual network computing client for X    
i   traceroute                      - Traces the route taken by packets over an 
i A xfce4-netload-plugin            - network load monitor plugin for the Xfce4 
$ aptitude search '~i ~d dhcp'
i A avahi-autoipd                   - Avahi IPv4LL network address configuration
i A dnsmasq-base                    - Small caching DNS proxy and DHCP/TFTP serv
i   isc-dhcp-client                 - DHCP client for automatically obtaining an
i   isc-dhcp-common                 - common manpages relevant to all of the isc

But which are the mandatory ones?

Thanks 🙏