Hi First of all thanks for the support each one are providing to everyone out there.I am new to this site and this is my first topic I am currently having a network(N1 - Class B network - 172.30.0.0/21). I have an ADSL router provided by the ISP which is hooked up to my FW Server. I have a switch and i have another 5 servers which is my DHCP,App,Database,File and Exchange Servers. There is another network(N2) in the same area.For N2 i am yet to find out the Class in which they operate and the subnets also.N1 and N2 are not connected to each other but they operate as individual networks. Currently it has been decided that N1 will merge with N2. I have my users in different buildings who are connected to N2. They use their Outlook to access the mails.I have enabled OWA for users. Also if my users(N1) want to access the shared files from N2,VPN has been enabled for those users for which security is given through my firewall.N2 has many subnets and they said that they will give us one subnet. I have had all sorts of questions going in my mind and no one to share.So i joined this forum to get ideas and to post my ideas as well. 1. will the Ip address scheming change for my network(N2) if N1 is operating on a differnet network.? 2.I have an HP switch would that be sufficient for joining N1 and N2.Or should i get a router for this case? 3. N2 network has got their own DHCP server,their firewall and everything. Is it possible for me to have my own DHCP server within the subnet that i will be using/getting? Also i dont want anyone from Network N2 to get Ips from Network N1.? Appreciate your help in advance. Thanks Thomas

1. will the Ip address scheming change for my network(N2) if N1 is operating on a differnet network.? >>> No, 2.I have an HP switch would that be sufficient for joining N1 and N2.Or should i get a router for this case? >>> Should be fine but better have a router if you plan to have different network address 3. N2 network has got their own DHCP server,their firewall and everything. Is it possible for me to have my own DHCP server within the subnet that i will be using/getting? Also i dont want anyone from Network N2 to get Ips from Network N1.? >>> If clients are plug to the same switch you make it complicated, the fastest or less busy DHCP will give IP address to requesting client. When clients boots it sends DHCP request broadcast, for sure DHCP will acknowledge. Question now is which one will ACK first? The DHCP from N1 or N2?

Thats a bit of a problem for the 3rd reply you have given. Is there a way for Network N2 to say that do not broadcast to the subnet of N1. Or is there a way for Network N1 to say that please broadcast only to N1 and not beyond that.

No, a switch is one broadcast domain. Place a router in between of the two networks so broadcast will not be heard by the other side of the network.