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172.16.0.0/12 subnet?

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blubomber

MIS
Dec 27, 2001
241
US
I was just curious. i am working for a new company that is using the 172.20.1.0/24 subnet for in house PCs. We are going to connect to another company via VPN. They are using 172.16.0.0/12. Does that subnet cover the whole 172.16.0.0 to 172.31.255.254? And if so, routing the information between the two companies over a VPN is going to be difficult right?

Thank you for any advice.

PS. This just shows that i need to brush up on my TCP/IP stuff.
 


172.16.0.0 is a Class B - Class B is used for medium-sized networks. A good example is a large college campus. IP addresses with a first octet from 128 to 191 are part of this class. Class B addresses also include the second octet as part of the Net identifier. The other two octets are used to identify each host. This means that there are 16,384 (214) Class B networks each with 65,534 (216 -2) possible hosts for a total of 1,073,741,824 (230) unique IP addresses. Class B networks make up a quarter of the total available IP addresses. Class B networks have a first bit value of 1 and a second bit value of 0 in the first octet.
They have the 172.16........ address block. The subnet mask is of the CIDR type in which they can further segment their allocation of IP address to best fit their environment.
Routing between the two should not be that difficult but I'd defer to someone who has done this, I have not but do know a bit about the OSI model, TCP/IP and Networking technologies.


Paul
 
Hi,

Routing should not be a problem at all, as long as they have no active hosts in your range ( 172.20.1.0/24 )

So for example, if you have a router on the local subnet, your routing table will probably look a litte like this.

172.20.1.0/24 CONNECTED
172.16.0.0/12 Serial 1/0 for example,

If they do have hosts in your range ( 172.20.1.x /24 ) then you may have to NAT, however I know VPN`s can be fussy with this.

LEEroy
MCNE6,CCNA2,3/4 CCNP,CWNA,CCSA,Project+
 
Thank you for the replies.

I will have to verify to see if there are any hosts that fall within our IP range. If so, i will look into NAT and other work arounds.

Thanks again.
 
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