Multiple Internet Connections - IP Conflicts

[witsendsolutions]

Hi Team,
I have partial solutions to my dilemma but none that match what I'm after, so I'm calling upon your expertise.
Our existing network runs a wireless 4g internet connection (don't ask, copper has been dug up). This is the gateway 192.168.1.1 (255.255.255.0)
We have a server running DHCP using 192.168.1.2 which allocates IP's to the network devices.
All desktops, laptops access the server for dynamic ips, and then out to the internet via 192.168.1.1.
We also have a building approx. 150 mtrs from our building that we communicate with using two Dlink AirPlus xtreme DWL-2100AP's (along with external antennas) (1 at each end).
192.168.1.50 & 192.168.1.250 (255.255.255.0) gway 192.168.1.1
Then in this building it is hardwired to wall sockets.

We (two weeks ago) had the Nbn connected (100/40) getting (95mbps/35mbps) which we want to use that NBN connections at both buildings and retain the 4g as a backup just in case.

The issue is that the NBN router is a Telstra Router (Netgear Devg2020) which uses the ip address of 192.168.15.1. If I change this to 192.168.1.1 (or other ip addresses) it looses the NBN connection, so I am stuck with using this range (192.168.15.1). It is like the firmware has been modded to only allow this ip range.

I DO NOT want to change the existing IP range in the main buildings as the servers need fixed ip address 192.168.1.2 etc. (worst case I will but would prefer not too as this is big effort).

I saw a post saying you can simply change the subnet mask to (as an example) 255.255.248.0 which will open up a ton more ip addresses (ie 192.168.1.1 thru 192.168.7.255) and both ip ranges can communicate on the same network. If so, I assume both routers including the access points will have to have this subnet.

Is this true, what issue would I face.

I really appreciate your advice and time.

 

[jsmithepa]

A mask of 255.255.255.0 will allow 254 devices, 254 will be the subnet size. If you need to enlarge this subnet, changing mask to 255.255.254.0 will double your subnet size. A client needs to see one and only one gateway.

 

[bill001g]

It should not care what ip block you use but there are some strange things out there.

You should be able to change your 4g router to say 192.168.1.254 and then use the telstra router on 192.168.1.1

If it does not let you change the ip it will likely not let you change the mask. You are in effect going to have to change all the ip on all the machines anyway because every machice must have the new mask. You dhcp server should give it out without users actually changing anything but the users will likely have a unstable connection until they get a new dhcp update, they will either reboot or release/rnew the ip.

The mask you want to use to overlap both those ranges is 255.255.240.0

Still I bet you can change the ip to something in the 192.168.1.x range

 

[AgPaul]

call telstra and complain. changing the ip address is a fundamental functionality that has to be included. there might be something they have to adjust themselves, but they should be able to change it for you