Question : WAN Network configuration

I have two Lans at different locations.
Now I want to make it a WAN with 64 kbps leased data circuit.
 
We have some doubts regarding connecting the LANs at both ends.
 
A-End Lan has IP addresses as  192.9.200.XXX  with
      subnet mask as 255.255.255.0
B-End Lan has IP addresses as  100.100.100.XXX
 
For connecting the LANs we have used Zytel 153X routers. These routers can talk to each other.

From A-End I am able to access B-End PCs where local router as a gateway has been configured under TCP/IP protocol.

However the same is not happening at B-End. That is B-End PCs are not able to access A-End PCs.
 
Please let me know if there is any problem with IP addresses at A-End or B-End end.
 
Thanks for your Help
 
Dilip Dandekar

Answer : WAN Network configuration

Are the IP addresses you have been assigned to you by someone like your ISP or are they just IP address you picked?

Basically, you are not using private IP address ranges - and you need to check your netmask for the 100.100.100.x network.  This network is in the Class B netmask 255.255.0.0 area.

Also, are you just connecting the two networks together or are you also using the same routers to connect elsewhere

Or are there any other routers on the networks?  In other words, are these two routers set as the default gateway for their respective network?

Or is there maybe a router to say an ISP on one of the networks?  If so, this router would most likely by the default router (and gateway) - so you need to add a static route in its routing table to tell it how to route traffic that is not going to the ISP to the opposite location.