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Remote LAN Access problem over VPN

I have established a VPN connection between two sites both with Cisco routers. I have 2 networks (192.168.1.0/24 and 10.10.35.0/24 ) on my side and I want the remote users to be able to access them both. I have one FE interface on my router and I configured it with 2 IPs; one IP from each network. The remote LAN is 192.168.100.0/24.
The tunnel is up but the remote LAN cannot access my LAN and vice-versa. what seems to be the problem here?
Someone please help me out.
Tags: networks
15th Feb 2011

Answers (7)

1 Vote
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IP helper address
remote clients have to get an address on the local lan to access resources. for Cisco, that would be an IP helper address. For Windows as the remote access server, that's a DHCP relay.
15th Feb 2011

Replies

Hi CG IT,
I have I have added an IP helper address on the LAN interface of the my router but the remote site users still can't access or ping any device on my LAN.
aw_willis@... 16th Feb 2011
1 Vote
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Router configs
Can you post the configs from the routers with the passwords masked.
16th Feb 2011
1 Vote
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walk yourself through the process...
where is the connection made? how are remote users going to get a local address? who issues them a local address? does the who, who issues local address, have addresses to issue?

IP helper works, but if there's no addresses to give remote users, doesn't help em much...
16th Feb 2011

Replies

Thanks for the response but what do I have to do to make this happen?
aw_willis@... 16th Feb 2011
1 Vote
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ip helper-address (dhcp server address)
that's the Cisco IOS command to forward UDP broadcasts to the DHCP server.

that is if your using a Cisco router...

honestly, you haven't given us enough detailed information to suggest a possible solution
Updated - 17th Feb 2011

Replies

I do not have a dhcp server on the network and therefore IP assignment is done manually. do I need a dhcp server to configure ip helper-address?
aw_willis@... 18th Feb 2011
1 Vote
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I'll go back to previous post of walk yourself through the process
how are remote clients going to get a local network address ? they already have one, that's not on the local network so .....
18th Feb 2011

Replies

My plan was to configure each workstation's NIC with 3 IP addresses and 3 default gateways. I've already configured some workstations already.
aw_willis@... 18th Feb 2011
1 Vote
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try it out, if it works there you go.....
.
18th Feb 2011

Replies

Ok, suppose I use dhcp on my router to assign IPs to remote users after configuring IP helper address on the remote router. How will the host on the remote learn be assigned a second IP since they already have an IP belonging to the remote LAN?
aw_willis@... 18th Feb 2011
1 Vote
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There's no learning involved by the remote client
it's how the frames are encapsulated with source and destination addressing.

DHCP simply provides remote clients with a local address including default gateway information which frames/packets are encapsulated with. The router then reads this [compares it to it's routing table] and knows how to route the packet. without this local network packet encapsulation, packets from remote clients still have the remote client address [which is the routable NAT address between public IP addresses] thus is unknown to the router [not in the routers routing table] and the router drops the packet.
Updated - 19th Feb 2011
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