Configure 1841 router and 2 PCs

Network newbie here. I'm using Packet Tracer to build a simple network with an 1841 router and two PCs. I can configure the router interfaces and power it on. How do the pcs get their ip addresses? I've tried giving the PCs static addresses but pinging from one to the other is unsuccessful. I also tried setting the PC for dhcp addressing but when I power on the router, the pcs still don't have ip addresses. Any suggestions?

Assuming each PC is attached to an ethernet interface on the router;

1. Each PC will need a default gateway. The default gateway address is the IP address of the interface the PC is attached to on the router.

2. Because it's a router the IP addresses on each ethernet interface on the router need to be in separate subnets.

3. Because you are attaching PC's to a router, the cables need to be crossover cables.

If you want the PC's to get their IP addresses via DHCP, you will need to set the router up to provide DHCP services, as they don't do it by default, or you need to add a proper DHCP server. But if you want to add a server, you'll need to add a switch as there isn't going to be a spare ethernet port on the router for the server to plug in to.

If you have a switch attached to the router, the router interface will need an IP address which will be the default gateway for BOTH PC's. Each PC will need a host address in the same subnet as the default gateway but that's it.

Ok since this is a basic network structure, avoid complications by using multiple router interfaces.
Use one router interface to connect to a hub. Note the IP address you assign to this interface.
Now add your hosts, and manually add the IP addresses to these hosts making sure they form part of the network IP address which you assign to that specific interface. E.g if you assign the eth interface on the router as 192.168.1.1, then assign the first host as 192.168.1.2 and 192.168.1.3.
Once you have done that, power up your hosts, and they will be reachable from either of them and the router as well.
Once you have achieved this, then go into configuring the DHCP function on the router, so that you can set IP addressing as DHCP on the hosts as well. That way you won't need to manually assign anything.
Let us know of the your progress

Just done it myself on an 1841 in Packet Tracer.
Here is the sho run output from the router:
[code:1]
Router#sho run
Building configuration...

Current configuration : 377 bytes
!
version 12.4
no service password-encryption
!
hostname Router
!
ip ssh version 1
!
!
interface FastEthernet0/0
ip address 10.1.1.1 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 10.2.1.1 255.255.255.0
duplex auto
speed auto
!
interface Vlan1
no ip address
shutdown
!
ip classless
!
line con 0
line vty 0 4
login
!
!
end
[/code:1]

1 PC has an IP address of 10.1.1.2 255.255.255.0 with a default gateway of 10.1.1.1 255.255.255.0

The othe rPC has am ip address of 10.2.1.2 255.255.255.0 with a default gateway of 10.2.1.1 255.255.255.0

The PC's can both ping each other. Remember when pinging for the first time you need to wait for AT LEAST the second ping to report. The first ping will be lost as the devices ARP for each other

Use a hub? If you're going to do that dump the router and let APIPA take care of connectivity. But no-one does that these days, surely?
If you want a more "real world" scenario, use a switch to connect to the router rather than a hub. *Much* nicer, and much closer to what you will actually see when you first encounter a production network

For a switch, connect both PC's to the switch with straight through cables.

PC1 has an IP address of 10.1.1.2 255.255.255.0 with a default gateway of 10.1.1.1 255.255.255.0

PC2 has an IP address of 10.1.1.3 255.255.255.0 with a default gateway of 10.1.1.1 255.255.255.0

Connect the router to any other ethernet port on the switch, again with a straight through cable.
On the port on the router that connects to the switch, configure an IP address of 10.1.1.1 255.255.255.0, and don't forget to add no shut. Again, both PC's will be able to ping each other, AND their default gateway. And you have the beginnings of a proper switched / routed network

Here's my step by step: Don't bother about using the CLI and router command, just set this using the GUI interface of Packet Tracer

1. On the router, configure eth 0/0 as 192.168.1.1, set it a default subnet mask of 255.255.255.0.

2. Now add your two hosts, name the first host PC 01, and the second host PC 02

3. Go into PC 01. Set the default gateway as 192.168.1.1, Set the IP adress as 192.168.1.2. Set the subnet mask as 255.255.255.0

4. Go into PC 02. Set the default gateway as 192.168.1.1. Set the IP address as 192.168.1.3. Set the subnet mask as 255.255.255.0

5. Now drag a hub into the setup. Don't bother about it's name, it doesn't matter right now.

6. Now deal with the cabling. You will need straight-through cabling for all your connections because all your connections are DCE-DTE connections i.e.
PC01/PC02 - HUB
HUB - Router

7. for PC01/PC02 to hub connection. use a straight-through copper cable and connect the following
For PC01 : connect the Fast ethernet port on the pc to Port 1 of the hub

For PC02: connect the fast ethernet port on the pc to Port 2 of the hub

8. For hub to router connection, use the straight-through copper cable and connect the following:
Port 0 of hub to eth 0/0 of the router.


Now ping away to glory, you will be able to ping the router from the pc and both pcs from the router.

This is your cheap and cheerful way of doing this.
As a next step you can try implementing the DHCP functionality of the router to set automatic IP adresses.

Once that is achieved, you can replace the hub with a switch, and create more efficient network structure
Let us know how you get along[/list]