Leased Line connection

Unanswered Question
Feb 8th, 2009

Dear All , I want some network design and configuration help from you.

1)Our main office has LAN Ip and we are going to connect another branch office with IP by 2 mbps leased line and 1841 cisco router with WIC2T card.Can anybody provide me the configuration of router for the same.Any Routing protocol will do.

2)In main office I have one 2000 Server as active directory.Is it possible to connect the users(XP) in the branch office to the main office active directory. If yes how???


I have this problem too.
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Giuseppe Larosa Mon, 02/09/2009 - 01:45

Hello Soumik,


if HQ has branch can use

if you have a leased line between the two sites you need a serial interface on both sides


the routing protocol can be eigrp

suppose you use on the serial line

router eigrp 100



no auto-summary

on branch

router eigrp 100

no auto-summary



note: EIGRP AS number must be the same

2) depending on how the users contact the AD you may need:

nothing if they use the AD ip address

an ip helper-address AD-ip-address

on branch router lan interface if they try to contact it via a broadcast

I think they should contact it by IP once they know how to reach it

you need for sure

ip helper-address dns-server-ip-address

Hope to help


soumik1979 Mon, 02/09/2009 - 02:33

Dear Sir

Thanks for your responce

Just one thing I would like to confirm that since this is only a point to point link, can I use static route instead of Dynamic routing.

Another thing I would like to confirm.We have a 1048 Kbps Iternet leased line at main office.It connects to a cisco 1841 router and then Cisco ASA 5510 firewall and from firewall it is distributed to our LAN.I want that the branch office internet access to be done through our head office internet.Can you help me regarding that...

Giuseppe Larosa Mon, 02/09/2009 - 03:34

Hello Soumik,

you can use static routing


ip route


ip route

about accessing the internet:

you need to modify the NAT statements so that also subnet will be translated to access the internet.

the ASA will need a static route pointing to HQ router to reach subnet

It's not clear where NAT is performed I guess on ASA but I may be wrong.

if not ASA it is made on the router with the internet link that can need a similar static route to know how to reach subnet

I would use EIGRP anyway because multiple devices are involved in the HQ site.

Hope to help


soumik1979 Mon, 02/09/2009 - 23:44

Now we are also going to connect a new branch which is within 100 meters of the main office.I have planned fibre connectivity and the LAN IP you help me regarding this.

Giuseppe Larosa Tue, 02/10/2009 - 07:11

Hello Soumik,

the configuration is very similar, the only differences are on the physical layer but it is even simpler

the new subnet will be

you may need to use a media converter from fiber to RJ-45 or you can connect the fiber to a LAN switch (better)

Hope to help


soumik1979 Tue, 02/10/2009 - 20:10

At present we dont have any VLAN at our main office.The main office has LAN IP new branch will have the IP I think we need to implement VLAN for this purpose.Please advice..

Giuseppe Larosa Wed, 02/11/2009 - 03:18

Hello Soumik,

yes you need a LAN switch to be able to handle two or more Vlans.

Technically you have a single VLAN / broadcast domain at your main office.

Moving to multiple Vlans is now a standard step.

Hope to help


soumik1979 Wed, 02/11/2009 - 04:58

Can you please tell me what switch is to use at main office and what to use at branch office.We are also planning to connect another office by leased line.How how things can be done.Can you give a outline for the same...

Paolo Bevilacqua Mon, 02/09/2009 - 02:35

Hi, you mentioned two network addresses that are the same. It is not possible to do that, the network adddress must be different.

Also, since clearly you are not a networking person, I suggest you hire a reputable technincian for the job, that will save you much time and mistakes.

soumik1979 Mon, 02/09/2009 - 02:37

Sorry, I made a mistake here.The IP will be and


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