Help with router config ?

aztec11us

hello all its my first time here so please escuse me if i posted in the wrong forum! see the attached immage capture from Packet Tracer i need help with the router called TERTIAR (on right side, the one with 192.168.1.1) how do i configure that router so that the PC3 connected to router TERTIAR si able to communicate with PC1 and with PC0 and Laptop0 to the left? stept by step pls the rest of the network has allready been configured and is working perfectly....i just dont know how to configure router TERTIAR thanks

markulous

That's too much work to walk you through step by step. I'd read some tutorials on how to set this up. You could post some configs and someone might help with that.

Are you using a routing protocol? Basically each device the packet goes to it has to know where to route it. If you don't have any routing protocols setup you'll need static routes setup on each router so it knows where to send packets from networks that aren't connected to it.

aztec11us

thank you for quick reply! the entire lab - EXCEPT for TERTIAR - is working perfectly !!! all routers are DHCP configured and all end devices are DHCP configured too! PC0 and Laptop0 on the left, have NO PROBLEM in ,,talking" to PC1 and Server0 on the right ! i used static routing between Router 0 and Router 1 (the two routers linked with red serial ) its ONLY that silly TERTIAR that's giving me issues :P i sense its about routing .... how do i statically configure it so PC3 can ,,talk" to the rest of the ,,world" in this lab ? thanks see the image for IPs

markulous

So the only thing that TERTIAR can ping is PC3 (and visa versa)? I'd post the running config if TERTIAR. Might be able to figure it out from that.

aztec11us

Regardint Router TERTIAR: FastEthernet 0/0 is towards PC3 ....FastEthernet 0/1 leads to the switch. both have been configured, as seen from below. I pasted the running-config for TERTIAR Building configuration...

Building configuration...

Current configuration : 646 bytes
!
version 12.4
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password-encryption
!
hostname TERTIAR
!
!
!
!
!
ip dhcp pool tertiar_supus
network 192.168.1.0 255.255.255.0
default-router 192.168.1.1
!
!
!
!
!
!
!
!
!
spanning-tree mode pvst
!
!
!
!
interface FastEthernet0/0
ip address 192.168.1.1 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 22.2.2.10 255.255.255.0
duplex auto
speed auto
!
interface Vlan1
no ip address
shutdown
!
ip classless
ip route 33.3.3.0 255.255.255.0 22.2.2.1
!
!
!
!
!
!
!
line con 0
!
line aux 0
!
line vty 0 4
login
!
!
!
end

Mitechniq

This is not the answer to your problem but you are adding a DHCP Scope 192.168.1.0 -192.168.1.254 and than statically assigning the first address DHCP will try to use to FA0/0. You need to add an "ip dhcp excluded-address" statement to avoid DHCP conflict. Usually I add this command first before I create my DHCP Scope.

aztec11us

Mitechniq wrote: »

This is not the answer to your problem but you are adding a DHCP Scope 192.168.1.0 -192.168.1.254 and than statically assigning the first address DHCP will try to use to FA0/0. You need to add an "ip dhcp excluded-address" statement to avoid DHCP conflict. Usually I add this command first before I create my DHCP Scope.

i see...i know how to use exclusions,. but in this lab, never had a problem!

as i ve said before, the entire lab is on DHCP, and the inside interfaces are static configured WITHOUT using exclusions, yet, EXCEPT for that damned TERTIAR, all the netweork is working just fine

so its most likely a routing issue!

thats what i want to know --- how to statically route TERTIAR so that PC3 can ,,talk" to the rest of the ,,world" too, just like all other end devices can with no problem

hurricane1091

I think that "default route" at the bottom needs to be this:

ip route 192.168.1.0 255.255.255.0 22.2.2.1


Probably need to see the other router's routes to determine if they need things done to them too.

aztec11us

Ok, here are the routes, statically configured:

Router0 - left side: 22.2.2.0/24 via 33.3.3.2

Router1 - right side: 11.1.1.0/24 via 33.3.3.1


on the left, notice please, that the LEFT network is: 11.1.1.0
on the right, notice please, that the RIGHT main network is: 22.2.2.0

now....how do i statically configure TERTIAR (and/or the other routers) so that PC3 can also ,,chat" with the rest of the lab?

hurricane1091

aztec11us wrote: »

THAT IS EXACTLY why i am asking for help !!!!

HOW do i statically configure Router TERTIAR so that PC3 can ALSO ,,talk" to the rest of lab, just like all the other end-devices can ?!?

well?
step by step ?

i know its a routing issue...if i knew the answer, i would not have posted this!

and if you read above, you'd know the rest of the network runs just fine! everything can connect to everything else...EXCEPT PC3 behind Router TERTIAR

Did you even set up the rest of the network or was that pre-configured? Probably don't have static routes configured to reach PC3 from the outside either.

aztec11us

ok then ...

pls configure a lab - but same scheme like the one in the picture !!!

feel free to use whatever IPs/ Ip class you like!

the only conditions:
- between routers, let it be static routing
- the IP assigning method must be DHCP (inside networks)

i made that lab myself...but please, redo it as you see fit

thanks

Mitechniq

This worked for me

Router 0:

ip route 22.2.2.0 255.255.255.0 33.3.3.2
ip route 192.168.1.0 255.255.255.0 33.3.3.2

Router 1:

ip route 11.1.1.0 255.255.255.0 33.3.3.1
ip route 192.168.1.0 255.255.255.0 FastEthernet0/0 (connected to the Switch)

Router T:

ip route 0.0.0.0 0.0.0.0 FastEthernet0/1 (connected to the Switch)

EdTheLad

Mitechniq wrote: »

Router T:
ip route 0.0.0.0 0.0.0.0 FastEthernet0/1 (connected to the Switch)

You should use "ip route 0.0.0.0 0.0.0.0 FastEthernet0/1 22.2.2.1" , without specifying the remote ip you are relying on proxy-arp being enabled on the R1 interface. If you disable proxy arp on R1, clear the arp cache on RT you will see your pings fail. This config also generates arp requests for every new destination, wasted time and resources.

A static route to exit interface should only be used on ptp links i.e. serial interfaces. Best practice is to disable proxy-arp everywhere, current ios has it off by default, your obviously using an old ios hence proxy-arp is enabled.

Mitechniq

You're right,
Just wanted to show different ways to configure the static route according to the diagram he presented.

aztec11us

Many thanks !!!

it worked perfectly

NOW ALL End Devices can ,,talk" to each other !


but i was wondering...can you please explain me, so i can learn rationally...why did the ip route 0.0.0.0 0.0.0.0 22.2.2.1 added to TERTIAR, worked so well ?

22.2.2.2.1 is the gateway to the second router (this one was the exit for the 22.2.2.0 network)

what does 0.0.0.0 0.0.0.0 22.2.2.1 mean ? what do those zeros do and mean?

many thanks

Mitechniq

It's what you would call your default route or more importantly your "gateway of last resort".

You could of easily added the 2 routes for the other networks like router 1 and router 2 but the "0.0.0.0 0.0.0.0" means all routes not found in your routing table will go to 22.2.2.1.

It is also indicated differently when you do a 'show ip route' by a 'S*'.

Not the best method because non-specific routes can cause routing-loops but you have a small network and I was trying to be quick and lazy...

hurricane1091

I gave you a default route which would send information from the 192.168.1.0/24 network to the next-hop router, which is fine but you would have needed further configuration on the other routers. What Mitch gave you was a route that forwards any traffic going into the T-T router but since you have nothing but the 192.168.1.0/24 network, nothing changes and it works perfect.

ip route 33.3.3.0 255.255.255.0 22.2.2.1 is the route you were using which is saying any traffic coming from 33.33.3.0/24 network should be directed to 22.2.2.1 but that makes no sense.

EdTheLad

Hurricane, i think you need to go back and learn static routing.

I think that "default route" at the bottom needs to be this:

ip route 192.168.1.0 255.255.255.0 22.2.2.1

TERTAIR has a local interface belonging to 192.168.1.0, so you don't need a static pointing to that network. Static routes for remote networks 11.1.1.0 and 33.3.3.0 pointing to gateway 22.2.2.1 are required.

ip route 33.3.3.0 255.255.255.0 22.2.2.1 is the route you were using which is saying any traffic coming from 33.33.3.0/24 network should be directed to 22.2.2.1 but that makes no sense.

This route means any traffic going to 33.3.3.0/24 send to gateway 22.2.2.1 which is perfectly fine. Looks like you have your logic backwards.

hurricane1091

EdTheLad wrote: »

Hurricane, i think you need to go back and learn static routing.



TERTAIR has a local interface belonging to 192.168.1.0, so you don't need a static pointing to that network. Static routes for remote networks 11.1.1.0 and 33.3.3.0 pointing to gateway 22.2.2.1 are required.



This route means any traffic going to 33.3.3.0/24 send to gateway 22.2.2.1 which is perfectly fine. Looks like you have your logic backwards.

I did mess up the first part of it, you're right. And I don't know why I was thinking that, but I wasn't that far off and I don't get to do this stuff at work so I'm not as proficient as I could be.

Instead of 0.0.0.0 0.0.0.0 fa0/1 you could do what I was going for still. Swap out the 192.x.x.x with the destination of 11.1.1.0/24 for example.

ip route 11.1.1.0 255.255.255.0 22.2.2.1 I see you were explaining something in regards to the interface versus the IP but that's beyond my scope of knowledge and I'm not in front of something where I can test this.

hurricane1091

Warning: A mess of unorganized thoughts below!

So going back and looking at the original question, the only route he has it then saying anything destined for for 33.3.3.0/24 use 22.2.2.1 which is not enough. If R0 was connected to the internet though and that was the public IP of R0, wouldn't that then be enough to reach the hosts behind R0 since NAT comes into play?

I get confused easily because I try to look at it from a real work perspective. If you could comment on this, I would appreciate it.

From this labs perspective, this TT router needs routes to 11.1.1.0/24 and 22.2.2.0/24, but does it need one to 33.3.3.0? I assume so, because a ping to those interfaces on the routers would not work without them, but you could still reach hosts in the 11.1.1.0/24 network, correct? But from a real world perspective then, if traffic going across the serial link between R1 and R0 was going across the internet and 11.1.1.0/24 was unrelated to 192.168.1.0/24, would the TT router need a route to the 11.1.1.0/24 network? NAT would be used and the public IP of R0 comes into play.


I know that's in depth, not related, and over thinking things, but while you're on this thread I figured I'd ask. I hope I'm not terribly far off in my thinking.