internet-sharingmacosNetwork
I'd like to share internet from ethernet (10.0.100.2) to Wi-Fi.
But when I do so and then I connect a device via Wi-Fi I get a whole different network: 192.168.2.0. Is there a way to use the same 10.0.100.0 network?
I need it because I have internal DNS and need to debug stuff over the LAN.
The issue was my proxy settings. I had proxy setting configured which were not valid for the network my host machine was connected to. For some reason this was not an issue over HTTP but HTTPS refused connections...
Check the IP address assigned to the device via DHCP. Does it match the IP range for the DHCP Network configured in Server.app's (disabled) DHCP service? I.e., is the IP address in the 192.168.1.0/24 range?) Also, try ifconfig -a on the Mac mini and look for a bridge that contains your WiFi device as a member. In the example below (MAC address obscured), I see that my WiFi device (en1) is in bridge100. Does the inet range for the bridge differ from the IP range assigned to your device?
bridge100: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
options=3<RXCSUM,TXCSUM>
ether xx:xx:xx:xx:xx:xx
inet 192.168.2.1 netmask 0xffffff00 broadcast 192.168.2.255
inet6 fe80::c82a:14ff:fe55:fc64%bridge100 prefixlen 64 scopeid 0xa
Configuration:
id 0:0:0:0:0:0 priority 0 hellotime 0 fwddelay 0
maxage 0 holdcnt 0 proto stp maxaddr 100 timeout 1200
root id 0:0:0:0:0:0 priority 0 ifcost 0 port 0
ipfilter disabled flags 0x2
member: en1 flags=3<LEARNING,DISCOVER>
ifmaxaddr 0 port 5 priority 0 path cost 0
nd6 options=1<PERFORMNUD>
media: autoselect
status: active
If so, try deleting the Network from the DHCP service in Server.app. This fixed the problem for me. After deleting the Network (I think I had to renew the DHCP lease, too), my devices are now assigned IPs in the range of the bridge.
I think that when Internet Sharing starts, it creates the bridge to support Internet Sharing. So your devices should get IP addresses in its range. I don't know why the Server.app's DHCP Networks interfere with Internet Sharing, since the service is off, but maybe because Internet Sharing forces DHCP on behind the scenes, and the Network settings are picked up regardless. I'm also not sure why an IP in the DHCP service's Network doesn't allow for internet connectivity, but I guess it may have something to do with not matching the bridge's network mask and/or some configuration of pf that Internet Sharing does behind the scenes.
I hope this helps.
Best Answer
You Mac is getting a single IP address on the LAN. To enable multiple devices to access the LAN, it creates a new private network on the Wi-Fi interface, and does NAT (Network Address Translation) between that network and the LAN. This is the same thing that happens when you connect your LAN (using private addresses) to the Internet using a router that gets a single public IP address.
Devices on your Wi-Fi network will be able to access devices on your LAN. Their IP address will be "translated" to your Mac's IP address, so devices receiving requests will see them as coming from your Mac. When they reply (to your Mac), your Mac will then do the reverse translation and send the packet down to the original device on the Wi-Fi network.
Note that this works well when devices on the Wi-Fi network need to access devices on the LAN. The other way around would be a problem.
An alternative is to use bridging instead of sharing. In that case, devices on both networks will think they're all on the same network (your Mac will forward frames from one network to the other). But this means that any devices on your Wi-Fi network will appear on the LAN (and use IP addresses there). Depending on your LAN's policies, this may or may not be an issue.