Can Network Manager be used for router-type configurations?

[Nick Howitt <nick howitts co uk>]

Hi,
I currently use ClearOS which is a CentOS derivative which can run as a 
full internet gateway and does not use Network Manager. I've been trying 
to evaluate Network Manager in Centos 7.4 to see if it can be used in 
ClearOS to manage the interfaces and so far I've struggled.

NM seems fine for running external interfaces and can easily join the 
Ethernet and WPA2 networks I have access to. Where I've struggled is the 
LAN interfaces.

For Wireless, the gui utilities have pulled some funny tricks on me, but 
I have been able to use nm-connection-editor to create a WEP secured 
hotspot. If I switched it to WPA/PSK I could never get a connection. One 
of my NIC's (EW-7811Un) would repeatedly ask for the PSK and the other 
(zd1201rw) seemed to authenticate but never pull an IP address. nmtui 
configured interfaces never even gave me a WEP connection.

I also tried through the command line with the zd1201rw NIC with:
nmcli c add type wifi ifname wlp0s18f2u2 con-name nick autoconnect no 
ssid TEST
nmcli connection modify nick 802-11-wireless.mode ap 
802-11-wireless.band bg ipv4.method shared
nmcli connection modify nick wifi-sec.key-mgmt wpa-psk
nmcli connection modify nick wifi-sec.psk "12345678"
nmcli connection up nick

But I failed to connect.

One thing I could not find in Hotspot mode was any way of controlling 
the IP range used by dnsmasq. If I gave the NIC a .1 address, it 
automatically used .10-.254 for its DHCP range. Is this controllable in 
any way? I could not see any nmcli options for this. Alternatively, can 
dnsmasq be disabled in hotspot mode? Also is it possible to set up any 
other DHCP options such as options 42 (NTP), 44 and 46 (for WINS)?

When testing on a wired LAN NIC I could find no equivalent of the 
wireless hotspot mode so I had to configure dnsmasq manually. Is there 
something I have overlooked?

TIA,
Nick