Connect Router to Internet

adam1995

Hi,

I have bought a 2651XM Cisco router and am trying to connect it to the internet. I have a BT business line and my BT hub is in bridge mode. I have a UTP cable going from one of the ethernet ports to the BT hub.

How do I connect the Cisco router to the internet?

Help will be much appreciated!

Thanks,

Adam

TWX

Please don't take this the wrong way, but simply "connecting the router to the Internet" is a gross oversimplification.

You need to know what you get from your ISP, like a network range, a static IP, or DHCP. You need to know if you're using only IPv4 or if you'll be dual-stacking IPv6.You need to determine what you want for your network, how large your network is, and that is somewhat dependent on what kind of service you get and how much incoming public connectivity needs to reach hosts on your network.

Once you have this information you can begin to design the specifics of your network, then you can figure out how to create the configuration that meets these specifics.

There's a reason why most people don't use commercial equipment at home, it's a lot more involved than setting up a consumer-grade broadband router.

adam1995

I do not have a static address with BT it is a dynamic address. I do not have any network requirements other than just wanting to be able to get out to the internet from the cisco router.

TWX

So, the cisco router is the only customer-premises device that will connect to the ISP?

If that's so, configure one of the ethernet interfaces with "ip address dhcp" and "no shutdown" the interface.

Just bear in mind, you would do well to configure virtual terminal "vty" security, "enable" security, hostname, and the like before you do this. If you put the otherwise unconnected device on the Internet and then start configuring it you run the risk that someone else might start configuring it for you...

adam1995

Yes thats correct, I just have a Cisco router in my house that I want to connect to ISP.

Do i run a straight through network cable from bt hub to cisco router? It doesnt seem to be picking up a DHCP address from ISP.

Hammer80

TWX: Save your breath he did not catch anything you said, you provided tons of info and he barely acknowledged it, he expects this to be plug and play.

adam1995: Not to be an ass but did you try "google" first. I just typed in "how to connect cisco router to the internet" and I got at least couple dozen links and youtube videos on how to do this. This is an enterprise level router, it is not plug and play, you have to configure it which means you have to connect to it via a console and use the command line. Also you might want to explain as why you want to do this in the first place, folks normally don't plug in their Enterprise Cisco Routers to the internet unless they have a very specific reason like remote access to their home lab, of course I am assuming this is in a home environment.

adam1995

thanks mate,

i have been following the word doc on this link; https://learningnetwork.cisco.com/docs/DOC-4212

I get an IP address from ISP but can't ping anything on the internet

my local LAN is on 192.168.10.0/24 and the LAN interface fastethernet 0/1 on the router is 192.168.10.14, i set DNS servers on WAN to 8.8.8.8 and 8.8.8.4, dialer 1 is getting the ip address, i would of thought fastethernet 0/0 should get it?

Nans

REMOVED UNNECESSARY QUOTED REPLY FROM PREVIOUS POST

Hi adam,

You cant directly connect the router to the ISP and expect it work fine. First did you see from what interfaces the router needs to send packet of the ping. If not you need to set a default route pointing the router to send the packets to that interface to which the ISP is connected to. Also as far as I know ISP will have DNS anyway but did you try looking at the configuration after the router was assigned an IP address.

I personally have no experience with this, but I thought of it in general manner and came up with this idea. So please try looking into this. Hope this helps.

Nans

adam1995

what would i need to set the default route to? can you set a default route to an interface rather than an IP address? the fastethernet 0/0 interface if connected to the BT hub that is in bridge mode.

mikeybinec

Is your BT handing out IP addresses? Because I've done that also--hook up a 2650 to the network (with a home type DLINK router handing out IP addresses) via fast ethernet, and use the ip address dhcp command. For pinging you also need to put in the ip domain lookup command also

adam1995

I have a DHCP server in my house doing DHCP on the LAN. not sure what you mean for the ping command.

The BT Hub is in bridge mode, so it is effectively like a modem.

mikeybinec

Do the crossover cable from your "hub' or what ever your gateway is

adam1995

you sure it needs to be a crossover cable from router to hub? I picked up an ip address on the dialer interface with a striaght through network cable? just cant ping anything on the internet as mentioned in earlier post

MTciscoguy

It won't hurt to try both a straight cable as well as try the cross over, they are not expensive, especially if you make them yourself.

TWX

Routers are typically pinned the same as end-user devices so that crossover cables are not necessary to connect them to conventional Ethernet switches.

MTciscoguy

I agree TWX, but I always suggest try it both ways, that way if you are learning you actually see how things work, instead of just asking questions, you get the real experience.

adam1995

ethernet seems to be working fine i am getting an ip address on the cisco router but can't ping out to the internet, I just don't know what I need to do now to get it working?

late_collision

It sounds like you need a default route.

adam1995

what do i need to set the default route to though?

fastethernet 0/0 is connected to the BT hub via bridge mode with no ip address

fastethernet 0/1 is the LAN adapter 192.168.10.14

and dialer1 is the interface with the IP address from ISP.

mikeybinec

How did you get solve the first issue? (getting an IP address)

You sure have a weird issue, since all of your other hosts can get addresses and DNS settings

A)Make sure you can ping the gateway, and probably put in ip route 0.0.0.0 0.0.0.0 (exit interface or next hop IP address) towards your gateway

B)ip domain lookup

TWX

What's dialer1 doing in the mix? Don't you connect via Ethernet to the BT device? Do you need PPPoE or something?

late_collision

adam1995 wrote: »

what do i need to set the default route to though?

Generally, static routes point to the IP address of the next hop.

An easy way to determine this is to take your modem/router out of bridge mode and allow it to pull DHCP from your ISP. Record the IP address, subnet mask, default gateway, and DNS settings.

Set your modem/router back to bridge mode and configure your Cisco router.

adam1995

yes I need PPPoE, i'm not sure what dialer1 is, i was just following the guide in the link i posted, it seems to have picked up an IP address from ISP though

adam1995

I just ran through the guide again and it started working. How do I know what the gateway is? It is only showing external ip when i do "sh ip int brief"?

volfkhat

Good for you dude!

Don't let people tell you what you can't do. You went & bought yourself the hardware, and you were determined to get it working.
Impressive :]

As for your (last) question,

What is your output for
show ip route

?

adam1995

Router#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

81.0.0.0/32 is subnetted, 1 subnets
C 81.151.119.142 is directly connected, Dialer1
172.16.0.0/32 is subnetted, 1 subnets
C 172.16.16.146 is directly connected, Dialer1

Jollycork

routers create their own networks, that is breakup a broadcast domain. So for any hosts behind your Cisco router directly connected to your ISP the gateway is your Cisco router's LAN address.

So you could put in the gateway of last resort as your Cisco Router's LAN address I assume that is 172.16.16.146 from the route table. your ISP assigned address is 81.151.119.142 for your WAN port.

If your ISP assigns addresses via DHCP, you can configure your WAN port for DHCP assigned addressing.

You'll have to create a pool of addresses for hosts behind your router for many to one NAT or NAT overload for hosts to get to the internet. Just remember that if you use ACLs that there is an implicit deny any any , at the end of the ACL.

just more stuff to play around with ...

adam1995

ok, i'll try "ip route 0.0.0.0 0.0.0.0 172.16.16.146" and see if that allows me to ping out to the internet from the router and get back to you guys

volfkhat

Fun thread!!
Definitely post back what happens :]

late_collision

adam1995 wrote: »

ok, i'll try "ip route 0.0.0.0 0.0.0.0 172.16.16.146" and see if that allows me to ping out to the internet from the router and get back to you guys

It won't.
With the above statement, you're trying to send off-network traffic towards your LAN.


Just as your workstations on your LAN need a default route to the gateway (the LAN interface IP Address of your router), your router, too, needs a default route over the WAN link.

Think about it, how does your router know where to route traffic? If you wanted to ping google's server 8.8.8.8, look at the route table in the router, do you see a route for the 8.8.8.8? Is there a default route? Based on the output of the "show ip route" command you posted above, the answer is no to both questions. If your router doesn't have a route, it drops the packet.

It would be best if you determined your default gateway made available by your ISP. I explained how to find this information in my previous post, by allowing your modem to pull the info.

You might be able to get away with using "ip route 0.0.0.0 0.0.0.0 Dialer1"

Jollycork

frames not destined for the local LAN are either discarded [ sent to the trash can] because the router doesn't know what to do with them, or sends them to the next hop router so long as the router knows what [who] the next hop router is.

You can turn on RIP Vs [well it's easy] to get an idea of routers exchanging route tables.

Many of us just give hints and not the actual answer.

Note: this also includes frame relay circuits from 2 other routers on the 172.X.X.X subnets...

R3640#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is 192.168.16.72 to network 0.0.0.0

C 192.168.16.0/24 is directly connected, Ethernet0/0
S 192.168.1.0/24 is directly connected, Ethernet0/1
C 192.168.2.0/24 is directly connected, Ethernet0/1
S* 0.0.0.0/0 [1/0] via 192.168.16.72
R3640#sh ip nat ?
nvi NVI information
statistics Translation statistics
translations Translation entries

R3640#sh ip nat translations
Pro Inside global Inside local Outside local Outside global
--- 192.168.16.112 192.168.1.100 --- ---


Gateway of last resort is 192.168.16.72 to network 0.0.0.0

172.16.0.0/24 is subnetted, 3 subnets
R 172.16.40.0 [120/1] via 172.16.20.2, 00:00:15, Serial0/0
R 172.16.30.0 [120/1] via 172.16.20.1, 00:00:10, Serial0/0
C 172.16.20.0 is directly connected, Serial0/0
173.55.0.0/16 is variably subnetted, 2 subnets, 2 masks
R 173.55.0.0/16 [120/3] via 172.16.20.2, 00:00:15, Serial0/0
R 173.55.107.0/24 [120/1] via 192.168.16.72, 00:00:02, Ethernet0/0
C 192.168.16.0/24 is directly connected, Ethernet0/0
S* 0.0.0.0/0 [1/0] via 192.168.16.72
Router#ping 192.168.16.72

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.16.72, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/4 ms
Router#ping yahoo.com


and here's how to do IP NAT

interface Ethernet0/0
ip address 192.168.16.111 255.255.255.0
ip nat outside
ip virtual-reassembly
full-duplex
!
interface Serial0/0
ip address 172.16.20.3 255.255.0.0
encapsulation frame-relay
no dce-terminal-timing-enable
frame-relay interface-dlci 321
frame-relay lmi-type cisco
!
interface Ethernet0/1
ip address 192.168.2.1 255.255.255.0
ip nat inside
ip virtual-reassembly
full-duplex
!
interface Serial0/1
no ip address
shutdown
no dce-terminal-timing-enable
!
ip http server
no ip http secure-server
ip route 0.0.0.0 0.0.0.0 192.168.16.72
ip route 192.168.1.0 255.255.255.0 Ethernet0/1
!
!
ip nat pool NATPOOL 192.168.16.112 192.168.16.117 netmask 255.255.255.0
ip nat inside source list 1 pool NATPOOL
!
access-list 1 permit 192.168.1.0 0.0.0.255
!
!
!
control-plane
!
!
!
!