CONFIGURING REMOTE SITES TO REACH THE CORE SWITCH 4

[drbk563]

Here is the situation. The layout of the network can be found at

http://www.virgoletta.com.

What I am trying to do is connect the four sites connect to the Hub router using EIGRP so that each site can talk to each other. What should happen is that all the users behind each router at each site should be able to reach core switch to reach the internet. I need some help with the configuration to get this working. In addition, the users at each site must get an ip address assigned to them via a DHCP server(143.104.179.1) which is located at the same location as the core switch.

Below is the config so far for the Hub Router and remote site 4. Please advise on what should be added or changed to get this working correctly.

Thank you in advance

Hub Router

interface GigabitEthernet0/0
ip address 143.104.179.239 255.255.255.0
duplex auto
speed auto
media-type rj45
negotiation auto
!
interface GigabitEthernet0/1
no ip address
shutdown
duplex auto
speed auto
media-type rj45
negotiation auto
!
interface Serial0/0/0:0
ip address 2.2.2.1 255.255.255.252
!
interface Serial0/0/1:1
description Circuit 32HCGS342365
ip address 2.2.3.1 255.255.255.252
!
interface Serial0/1/0:1
description Circuit 32HCGS342436
ip address 2.2.4.1 255.255.255.252
!
interface Serial0/1/1:1
description Circuit 32HCGS342273
ip address 2.2.5.1 255.255.255.252
!
router eigrp 101
network 2.2.2.0 0.0.0.3
network 2.2.3.0 0.0.0.3
network 2.2.4.0 0.0.0.3
network 2.2.5.0 0.0.0.3
no auto-summary
!
ip route 0.0.0.0 0.0.0.0 143.104.179.254

*************************************************************

Remote Site 4

interface FastEthernet0/0
ip address 3.3.3.2 255.255.255.192
ip helper-address 143.104.179.1
speed 100
full-duplex

interface Serial0/1
ip address 2.2.2.2 255.255.255.252
service-module t1 timeslots 1-24
!
router eigrp 101
network 2.2.2.0 0.0.0.3
no auto-summary

 

[burtsbees]

Is it important that you use a separate server for DHCP rather than configuring the router to do so? The reason I ask is because routers by default do not forward broadcasts, which include DHCP requests, ACK's, etc, but it is not difficult to get the router to forward DHCP requests...can't remember off top---something like ip helper command...have to look it up---let us know if you want the router config'd as a DHCP server.

Burt

 

[Minue]

Hello
So far you are heading any the right direction.Try first to get connectivity and EIGRP working and then the DHCP.
I have notice that the HUB router is using subintefaces what WAN technology are you using?Can you ping the spoke router?
Regards

 

[drbk563]

I already have a separate server which will take care of DHCP requests. I am using T1's running HDLC. Yes I can ping the spoke routers.

 

[Minue]

Hello
I thought you were running frame relay.But if you can ping the already configured spoke things are going well.Is the Eigrp routing working are you getting updates for the LAN subnets configured on the routers?
Regards

 

[burtsbees]

You never mentioned what the problem is...

Burt

 

[Minue]

Hi Burt
I don't think he has a problem as yet.It look like he's setting up a new site and needs help with the configuration.I think he's heading in the right direction.There's no troubleshooting to be done as yet because the configuration isn't complete.From what I see he's using a channelized T1 to the remotes routers.So no problem reaching the remote site.The Eigrp should work without problems as well.The DHCP servers will give the clients there address.And all routers should point to the core switch as the default gateway.I think he will find the problem here,(I can't figure out how the clients will get on the Internet without some NAT.)Do you have any ideas?
Regards


Regards

 

[drbk563]

Past the core switch there are more devices such as the ASA Firewall which will handle the NAT. I just want to make sure that the configuration at the hub router and the remotes sites is correct so that the users at each remote can reach the core switch and vice versa. If the users can reach the core switch then they will be able to reach the internet.

Thank You

 

[Minue]

Well as I said you are on track!Let us know how it goes.
Regards

 

[burtsbees]

If you need DHCP to go through the hub router, then you need the ip-helper address line in the hub router also.

Burt

 

[drbk563]

When you say configure the ip-helper address do you mean on the serial of the hub or the Ethernet of the hub?

Thank You

 

[burtsbees]

Whatever interface(s) a DHCP broadcast needs to go through. You already have one helper address configured---is this the interface pointing toward the LAN where the nodes that are needing the DHCP's reside?

Burt

 

[Minue]

Hello
I thought about what you said "separate server which will take care of DHCP requests"
But where will be these DHCP servers?If you are hosting tem on the LAN subnet you will not need the "ip helper address" command.
Regards

 

[burtsbees]

Yes, Minue, true---however, he states that the first config is for the hub router, like the LANs are "spokes", therefore I assume the DHCP server would need to cross the router to divy out addresses on the other LANs. This is why I was suggesting to simply config the router to do the DHCP---then, he could sell the DHCP server on Ebay.lol But I agree---you are correct if he plans to DHCP the addresses on a LAN behind the router only.

Burt

 

[Minue]

Yes!Your recommenation is good as well.What's strange that in his first mail,he indicated that he wanted to use this DHCP server(143.104.179.1) in the core.But in the reply to you he said he has different DHCP server.In any case the config isn't that difficult.
Regards

 

[burtsbees]

Yes---looks like according to his drawing the DHCP server he plans to use is on the Core Switch subnet, and site 1, 2, 3 and 4 are all on different subnets, and it looks like he wants these sites accessed via the hub router. I think the hub router needs the simple DHCP config. Thanks, Minue.

Burt

 

[drbk563]

So besides adding the IP-helper address on the spoke I also have to add it on the HUB router serial ports? Also, there is only one DHCP server which has an ip address of 143.104.179.1. Which is located in the same subnet as the core switch.

 

[Minue]

Hello
No you won't need it on the serials of the Core.I don't no why you prefer it this way,but a cleaner solution would be to configure all spokes router to give the client their ip address.Because the ip address helper command will allow broadcast for a total of 8 protocols,that's a lot of broadcast.
Regards

 

[burtsbees]

Actually, I think he will need it on the serial interfaces if there are clients off of the erial interfaces that will need DHCP.

Burt

 

[plshlpme]

all the spokes will need the helper on their wan links.. not the core.

the spokes would then take the broadcast and send it as a unicast to the helper address correct?
so the hub router wouldn't require any special config as the traffic would be unicast at that point and would be free to pass...