Hi,
at one of my clients I need to join two networks into one, because finally they got 10 Gbps Optical line inbetween. Until now they were using interconnect link via 2 DSL routers. Ok, here we go:
OLD SITUATION (until today)
* LAN 1 ****** 200 IP devices
192.168.0.1/24
Subnet mask: 255.255.255.0
Main Router IP: 192.168.0.1
DSL router IP: 192.168.0.50
* LAN 2 ****** 100 IP devices
192.168.79.1/24
Subnet mask: 255.255.255.0
Main Router IP: 192.168.79.1
DSL router IP: 192.168.79.50
On both MAIN ROUTERS there is a route added for other network, so traffic destined from LAN1 to LAN2 (or vice versa) is routed on proper DSL ROUTER.
NOW, NEW CONFIGURATION (today)
They've got 10 Gbit optical dark fibre and FO-2-ETH adapters between both LANs.
Now, I need some suggestions how to utilize this link best. How should we proceed?
As we think of expanding subnet, for example to 192.168.0.1/23 (subnet mask 255.255.254.0), we realize that we won't be able to change all network device settings at once, but it will be a long process (more than 300 IP devices, lot's of them with static IP).
So QUESTIONS:
1.) Since by changing subnet to 255.255.254.0 we'll change broadcast address to 192.168.1.255, what could get broken in the process? I mean, when some of devices will have new subnet, and others old...will they be able to communicate?
2.) Should we start by changing IP/SUBNET on router/firewalls first, then servers, then clients.....or vice versa? I tested changing subnet on my PC, and from client side it all works from new IP and new subnet mask. But I did not try changing subnet on router.
NEXT QUESTION is about DUAL GATEWAYS.
Ok, when above config will be finished, there is one main problem:
We do not want all clients to use 1 gateway, but would like some sort of load-balancing. Each single gateway is on weak WAN connection (ADSL), so it barelly handles existing traffic, which is why we do not want further joint traffic to route via single ADSL.
So how to set this up?
WAN Routers are on one side LINUX machine on CentOS, and on the other side Cisco 800 series.
A simple FAILOVER can be established by configuring DHCP to provide 2 Gateways to clients. But this does not split traffic, neither provides load balancing.
Any idea?
192.168.0.1/23 will be able to communicate with 192.168.0.1/24 devices
2. It does not matter, if your firewall and servers will have addresses in 192.168.0.1-192.168.0.254 range. If you change subnet masks on them, they will still be able to communicate with other PCs in 192.168.0.1-192.168.0.254 range.