Packet Tracer

[joshuadukes0]

Hi, 

I'm having a routing issue with part of my packet tracer network.

I have resolved the connectivity issues which allows PC0 and PC1 to connect to the webserver. 

However I'm having an issue with the last part of the network but I have already resolved a couple of issues. 

One of the Wells router sub interfaces didn't have an IP configured I have now assigned the correct IP, I can ping both sub interfaces from both PC2 and PC3. 

- I have made sure that trunk port is set to both the switches. 

- Ensured the VLANS are present on the Somerset Levels switch. 

- Checked the that routing is in place to the 123.0.0./24 network from both 192 networks. 

Please can someone provide some things for me to check, the combination of a switch, router then switch has really confused me and I'm stuck on what configurations to check next

[Joseph W. Doherty]

Probably save time if you would attach your PT file.

[joshuadukes0]

Hi Joseph, 

Thanks for getting back to me. 

I have attached the PT file, I believe the issue is something to do with static routing and not for anything basic like trunking or missing VLANS. 

I did add static routes from the sub interfaces from the Wells router, but sill unable to ping the webserver from PC2 or PC3. 

Just to mention i am aware that i need to add static routes from Street router to Glastonbury router for that connectivity to work which I know how to do. 

Its just getting the connectivity from PC2 and PC3 working to the webserver is the focus for now, tracert stops at Wells.

Looking forward to seeing your thoughts 

Thanks 

Josh 

[joshuadukes0]

I believe I may of resolved this issue. 

The static routes required to be added between each router on each segment. 

This due to the default gateway of the webserver being the 'Street' interface (123.0.0.1) 

I now have connectivity to web server from all PC's to webserver via browser. 

[Joseph W. Doherty · Accepted solution]

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@joshuadukes0 wrote:

I believe I may of resolved this issue. 

The static routes required to be added between each router on each segment. 

This due to the default gateway of the webserver being the 'Street' interface (123.0.0.1) 

I now have connectivity to web server from all PC's to webserver via browser. 

---

Ah, just sat down now to look at your attachment, and I now see you've self resolved your issue (which is great).

An important thing to remember about routing, "somehow" the router needs to know where to send packets for destination networks.  Generally, a router implicitly knows about the networks it's direction connected to, so something like

192.168.1.0/24 <> router <> 192.168.2.0/24

the router can route between 192.168.1.0/24 and 192.168.2.0/24

but for something like

192.168.1.0/24 <> router1 <> 192.168.2.0/24 <> router2 <> 192.168.3.0/24

router1 doesn't know how to reach network 192.168.3.0/24 while router2 doesn't know how to reach 192.168.1.0/24.

So, in a case like the last, "somehow" we need to inform routers 1 and 2 about the network they don't have a direct connection to.

This might be done by using static routes and/or using a dynamic routing protocol.

Now, when you write "This due to the default gateway of the webserver being the 'Street' interface (123.0.0.1)", the real issue is, what did the Street router "know".

Basically, by default, and with correct gateways configured, all your hosts could send traffic to the Web Server (do you understand why), but whatever router, of the 3, the web server directed its traffic to, had to "know" of the routes beyond the other two routers.

Possibly, you have have painted yourself into a corner, if you've only added static routes to the Street router.  If it fails, what happens then, if you change the Web server's gateway to .2 or .3?  Will part of the network, behind the updated non-gateway router be reachable?

It may be too soon in your studies, but on the Web server side, you could define a virtual gateway, across all 3 routers, and if the active gateway failed, one of the other two routers would become the new Web server gateway, but again, for that to work correctly, the router that becomes the new gateway router needs to "know" about the other networks.

If you have additional questions on the above, feel free to post follow-up questions.

[joshuadukes0]

Thank you very much for the great advice, its a great way to think of routing between different ranges/networks. 

Especially if I combine it show commands such as show ip route & show ip route static | begin Gateway.