IP Addressing -------------------

[panlamture]

Hi All,

Lan A|Router A|--Internet--|Router B|Lan B

Above is my network Diagram, and ip addressing for the dia is as, Note that this is DSL connection i am getting the Wan ip address from ISP.

Router A Ethernet : 200.200.1.0/29

Router B Ethernet : 200.200.2.0/24 (Whole Class C)

Now my 4 server having ip's at router b side.

i.e

Server 1 : 200.200.2.4

Server 2 : 200.200.2.6

Server 3 : 200.200.2.8

Server 4 : 200.200.2.10

Question : Now i am shiftting my above 4 server from router b side to router A side, and do not want to be change the ip's of server.

Is it possible that should i use first 16 ip address from 200.200.2.0/24 on router A side and remaining ip from 17 to 255 to be use on router B side, so my server will not get change ip.

If Yes,

Pls let me know the Ip address subnetting for both the location .

like what will be the network id broadcast id for both network and subnetmask.

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remember that

1. i do not want to change the ip address of server.

2. Useing the ip address above 200.200.2.0/24, how can i use at bothside.

3. I wanted first 16 ip's to be configured on Router A side only not more then 16 IP's.

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[thisisshanky]

Yes, you can do that.

Split 200.200.2.0/24 into two subnets

200.200.2.0/25 and 200.200.2.128/25

Assign 200.200.2.128/25 network to Router B's ethernet. Valid hosts in this subnet range from

200.200.2.129-254.

Assign a secondary address to router A's ethernet as follows

int e0

ip add 200.200.1.1 255.255.255.248

ip add 200.200.2.1 255.255.255.128 secondary

When you move servers from B to A, you wont have to change the ip address on any of the servers.

PS: My subnetting scheme would give you 126 valid hosts on either sides from the 200.200.2.0 subnet. Since you need only 16 or so many ip addresses for the servers on side A, this can be a wastage of ip address on side A. For this use a more specific mask such as 200.200.2.0 with mask 255.255.255.224 which will give you 30 valid ip addresses in the 200.200.2.0 subnet.

Hope thats clear

[anand]

Hi,

i don't think so that you can't use the "B" WAN IP address on "A" side, because your ISP would have routed the public IP of 200.200.2.0/24 only to the "B" side. if it is possible to hav 200.200.2.0/24 to be used on the "A" side,in that case even if some one comes to know about your WAN IP address, he can use it else where across the world, i hope you agree with this, isn't?

[thisisshanky]

Anand's response is very valid. Lets back track a little from my original post, and consider whether the subnets 200.200.2.0 and 1.0 are owned by you (assigned to you by your ISP). If both locations are handled by the same ISP, (which I think is true - since both blocks are contiguous) you can talk to the ISP to route a subnet of 200.200.2.128/25 to site B, while routing 200.200.2.0/25 to site A.

Hope that helps!