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Home connection to Central Office using the internet.

bluez asked
Hi guys
sorry if this is going over old ground
I am trying to setup IIS in a DMZ so our sales guys can access their mail using web outlook.
If I'm using the internet to connect over ip how do I get a connection to the CO?
I understand how to connect two routers back to back. But how does interesting traffic open the isdn line for eg our cisco 1600 CO router over the internet?
Has anyone done anything similar.
What is particularly confusing is this.  If from the CO I want to send an email, the router will sense interesting traffic on eth0 and bind to the bri0 port connecting to the isp next hop lets say 0845222170.  That I understand but how is my router dialed up from the internet?
Also I belive I may need to use a VPN connection
Many Thanks
Watch Question

Traditionally, ISDN for Internet utilized for browsing based connections, since the customer can control the connection to the Internet based on the requests made.  However, whenever you have inbound connections over that ISDN link, both parties need to be able to dial each other.

Since this involves a scenario that could have traffic initiated from either side, you would need to have your ISPs on both sides be able to dial in to their respective office when there is inbound traffic.  Unfortunately, there are a number of other things that could randomly bring up your connection in this scenario driving up your costs, such as someone doing a simple ping against your IP address.  Also, when you have a site to site conneciton, you will need to be very careful on what traffic can pass back and forth, as you will probably not want simple MS browse traffic etc keeping the line up unneccessarily.  Due to this added cost and complexity, you may want to check into other technologies that may be cheaper depending on your situation, such as DSL or Cable.  Also, I have seen some ISPs that offer an "always on" ISDN connection for a flat monthly rate.

Your need for a VPN is dependent on what traffic needs to go back and forth.  For that matter, it also affects many of the things I mentioned above.  If it is simple email, basic SMTP could be used - and maybe add some PGP technology for encryption.  However, if it goes beyond this, and people need access to public folders in Exchange, or a multitude of other things, a VPN may be more appropriate.

Hope this helps.
Like Scraig indicated having ISDN at the CO would mean the ISP dials your router and consequently (at least in Europe) they would have to pay for the connection cost.
ISDN is best used for a direct RAS-connection to the CO.
If you want to use the internet you need to have a fixed connection to the Internet at the CO-site (such as leased-line or ADSL with fixed IP-address)
Kind Rgds


If I have a kilostream link to the Internet, I understand the route is a direct connection.  What then would be a suitable topology.
For my CO what distribution/core hardware should I use? an Access server or for eg cisco 3600?
Could I use my existing cisco 1600 and purchase a WIC?

Many Thanks

You certainly could use the 1600 and add a WIC.  The main difference between the 3600 and 1600 series is scalability.  With the 3600, you get more slots, processor, and memory, allowing a larger variety of topologies and connections, and better throughput at higher volumes.  However, if all you are doing is hooking up a single BRI connection, the 1600 will suit you just fine.  If you want an intermediate between the two, you could think about the 2600 model.


When you say an intermediate is this to aggregate the network.  Can you explain
Many Thanks.


What I mean is that the while the 1600 will probably work well for your situation, it has no real ability to scale to any larger of an implementation.  On the other hand, a 3600 has the ability to scale to a rather large implementation.  If you see some need to possibly increase the size or capacity, yet do not need the size (and cost) of the 3600, the 2600 is good "middle ground" fit giving you additional WIC slots and processor and memory capacity, without the cost and size of the 3600.
Les MooreSr. Systems Engineer
Top Expert 2008

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