How to connect to the provider's network?

[Ethanol]

Hello.

I want to set up internet in my apartment. I have a home computer and a Cisco 1841 router.
My provider provided me with the following connection information:

login (mylogin)
ip-address (10.1.57.21)
netmask (255.255.255.0)
gateway (10.1.57.3)
dns (10.0.0.1, 10.0.0.2)
vpn (vpn.provider.ru).

I also know that the provider uses l2tp.

How should I configure my 1841 router so that my computer has Internet access?

I can configure the ip address on the ports and raise "dhcp", but I do not know what needs to be configured further.

I will be very grateful if you explain to me the further necessary actions and commands.

Thank you.

[Richard Burts]

My first comment would be that if you have only a single PC and the 1841 then you do not really need the 1841. You could just connect your computer to the provider and configure the PC with the information that the provider gave you.

But you asked a question about how to configure the router and I will answer that. Here are the minimum things you need to do to set up the 1841 and allow your computer to connect to it and to access the Internet.

1) configure an interface (probably Fa0/0) with the IP address and mask given by the provider. (remember to no shut the interface after you configure it)

2) choose an IP subnet for your inside connection. (perhaps use 10.10.10.0)

3) configure an interface (probably Fa0/1) with an IP address and mask from the subnet you chose. (remember to no shut the interface after you configure it)

4) configure your PC with an IP address and mask in that subnet. Configure the PC default gateway as the IP assigned to the router interface. Configure DNS on the PC using the addresses supplied by the provider. An option could be to configure the router with a DHCP pool and have the PC use DHCP to learn its address - but that adds complexity to the config and I suggest that you keep it simple.

5) connect the PC to the router interface. If you are connecting the PC directly to the router interface you might need an Ethernet cross over cable rather than an standard straight through Ethernet cable.

6) configure a static default route using the next hop supplied by the provider.

7) configure address translation so that traffic from the PC to the Internet will be translated using the router outside interface IP.

If you do these things correctly then your PC should have access to the Internet.

HTH

Rick

[Georg Pauwen]

Hello,

since I was working on this, I might as well post it, in addition to Richard's port, and without wanting to be redundant.

The config would look like this (important parts marked in bold). The L2TP is (probably) for remote access VPNs, do you need that ?

Current configuration : 816 bytes
!
version 15.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname 1841
!
boot-start-marker
boot-end-marker
!
enable password cisco
!
no aaa new-model
ip cef
!
ip dhcp excluded-address 192.168.1.1
!
ip dhcp pool LAN
network 192.168.1.0 255.255.255.0
default-router 192.168.1.1
dns-server 10.0.0.1 10.0.0.2
!
username admin password 0 cisco
!
interface FastEthernet0/0
description WAN Link to ISP
ip address 10.1.57.21 255.255.255.0
ip nat outside
duplex auto
speed auto
!
interface FastEthernet0/1
description LAN
ip address 192.168.1.1 255.255.255.0
ip nat inside
duplex auto
speed auto
!
ip forward-protocol nd
!
ip http server
!
ip nat inside source list 1 interface FastEthernet0/0 overload
!
ip route 0.0.0.0 0.0.0.0 10.1.57.3
!
access-list 1 permit 192.168.1.0

[paul driver]

Hell0
Another possible solution seeing as your isp looks like they are already performing network translation and providing you with a 10.1.57.0/24 subnet to play with is to irb bridge the connection between the isp and your rtr this will allow you to use your pc and any other hosts you may wish to utilize with that subnet and you shouldn't then need to configure any NAT of your own and even maybe DHCP as this would be provided by your isp.

your rtr

Conf t
bridge irb
bridge 1 route ip
bridge 1 protocol ieee

int fa0/0
description ISP facing
no shut
bridge-group 1

int fa0/1
description LAN facing
no shut
bridge-group 1

int bvi 1
ip address 10.1.57.12 255.255.255.0
exit

ip route 0.0.0.0 0.0.0.0 BVI1 10.1.57.3

[Richard Burts]

@paul driver makes an interesting suggestion that I had not thought of. And thinking about it I am not sure that you necessarily need IRB. I think it would be sufficient to just do these steps:

- no ip routing 

- bridge 1 protocol ieee

- on each Fa interface no shut
   bridge-group 1

This would enable bridging on the router and allow your PC to communicate with the ISP directly.

HTH

Rick

[paul driver]

Hello @Richard Burts 

Your very much correct mate i didn't need to use IRB however my reasoning was to utilize the supplied ip address in the rtr configuration the OP stated they were given by their ISP, which without enabling IRB i would not have been able to accommodate its inclusion.

[Richard Burts]

@paul driver makes an assumption that the provider has given you a /24 subnet to use. If that is the case then it makes sense to want to use 1 IP in that subnet on the router and to use another IP in that subnet for your PC (so no need for any address translation). We do not know much about this ISP and what it has assigned and I do not necessarily share that assumption. I believe that another reasonable assumption is that 10.1.57.0 is a subnet used by the provider for customer connections. You are assigned an IP in that subnet and that other customers are assigned other IPs in that subnet. If this is the case and you assign another IP in the subnet to your PC then you may be duplicating an address used by someone else connecting to this ISP. If you do not assign the IP to the router then you could assign that IP to your PC (it works with no need for address translation - if you had more than one device then there would be a need for your devices to be in a separate e subnet and for the router to perform address translation).

Both of these are reasonable assumptions. Perhaps the original poster can check with the ISP and let us know which one is used by the ISP.

HTH

Rick