Packet Tracer Hosts Not Reachable Outside Subnet and VLAN

[cyberstudent]

Hello everyone,

This is my first post here, and I apologise if it is in the wrong section, but I really am hitting a roadblock with this.

I have a project where separate departments have their own subnet and vlan. Within the subnet and VLAN, the hosts are reachable to each other, however once you try and ping a host in a separate department (different VLAN and Subnet) then that host is unreachable.

Additionally, the email server, HTTP server and DNS server is not reachable even from hosts within theh same VLAN and subnet.

For the life of me I cannot figure out why this is, I really would appreciate any assistance with this.

I have attached the packet tracer file as a zip below for reference.

Thanks so much, really.

[matthew2587]

To start, look at your dhcp pools and make sure to exclude the DG address. Currently some PCs are using their own address as the DG. Also, check your VLAN config. ex. pc in vlan 70 has a DG that is in vlan 10.

[Georg Pauwen]

Hello,

the problem is that your DHCP pools and static assignments use the wrong default gateways. The gateways need to match the actual IP addresses of the respective Vlan interfaces.

In order to avoid confusion, I fixed all DHCP pools and assigned all PCs dynamic DHCP addresses. The revised file is attached...

[cyberstudent]

Hello,

Thank you for making the changes - I've looked through your file and assigned the correct gateway to the hosts but it seems that the hosts on different vlans are still unreachable, maybe it has something to do with the router? I apologise asking for help again but I have attached the updated file.

[Georg Pauwen]

Hello,

which hosts do not work ? If you set the IP address to DHCP, the correct addresses should be assigned.

I have found one more mistake, there was an unused DHCP pool with a duplicate default router. Open this file, let all the PCs get an IP address, and then specify which PCs are not getting access outside of their own Vlan.

[cyberstudent]

All of the PCs not in the same vlan are not reachable between each other. For example PC-PT 28 in Research Department cannot reach PC-PT 161(1) in Management department. 

[Georg Pauwen]

You do not have 'ip routing' enabled on the layer 3 switches, also, there is no routing protocol or static routing configured anywhere. I have enabled 'ip routing' on the layer 3 switches and added OSPF as a routing protocol. I do not have access to the routers, but add the following on all routers:

router ospf 1

 network 0.0.0.0 255.255.255.255 area 0

Or post the router passwords...

[cyberstudent]

Thank you! I have correctly configured the routes with ospf, now hosts on the same L3 switch are reachable, such as PC-PT test-pc  in the IT department, and PC-PT 36 in the Server room. However   hosts are still not reachable when one host belongs to one L3 switch, and another host belongs to a different L3 Switch.

E.g please see screenshot

Also for router 3, the username: cam        passwords: nccd

Attached is updated file, thank you!

[Georg Pauwen]

Your IP addressing overall is incorrect. You have overlapping subnets on the various layer 3 switches and routers. What IP addressing scheme are you following, or supposed to follow ?

[Martin L]

To show off what PT can do and support, PT developers have included some samples of tech with configs (under File, Open sample).  u can always find some close to your issue; open, study/investigate and apply to your lab.

Regards, ML
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