Cisco Packet Trace issue with routing

[claudemichel]

I have the routers connected to each other with point to point connections to which I assign the IPs starting from the address 192.168.25.80/30. The problem is connecting the LANs to other LANs. Having clearly set the gateway, it is a LAN network whose addressing plan is based on 192.168.25.0/24 to be subnetted with vlsm with /28 for Lan and /30 for router.

[Joseph W. Doherty]

What's the issue?  You can certainly allocate /28s and /30s out of a /24.

[antisocial11224]

---

@claudemichel wrote:

I have the routers connected to each other with point to point connections to which I assign the IPs starting from the address 192.168.25.80/30. The problem is connecting the LANs to other LANs. Having clearly set the gateway, it is a LAN network whose addressing plan is based on 192.168.25.0/24 to be subnetted with vlsm with /28 for Lan and /30 for router.

---

Please Ensure you have a clear network addressing plan. For point-to-point router connections, start with the 192.168.25.80/30 subnet and assign unique /30 subnets for each link. For your LANs, use subnets from the 192.168.25.0/24 range, specifically with /28 masks. For example, you can use 192.168.25.0/28, 192.168.25.16/28, 192.168.25.32/28, and so on for your LANs. Make sure each subnet is correctly assigned and that your routing tables on each router are properly configured to include routes to each LAN subnet. This approach should help you establish proper connectivity between your LANs.

[Martin L]

you can attach your PT file here in a zip format for use to check it

Regards, ML
**Please Rate All Helpful Responses **

[mohamedlamine]

It seems like you are setting up a network with specific IP addressing requirements. To connect the LANs to other LANs with VLSM (Variable Length Subnet Mask) using /28 for LANs and /30 for routers, here is a suggested addressing plan based on the information provided:

1. Subnet the 192.168.25.0/24 network into smaller subnets using VLSM:

   • LAN subnets will use /28, which gives you 16 hosts per subnet.
   • Router point-to-point links will use /30, which gives you 2 usable IP addresses per subnet.

2. Assign IP addresses starting from 192.168.25.80/30 for the point-to-point connections between routers:

   • Router 1:
     • Interface connecting to Router 2: 192.168.25.80/30
     • Interface connecting to LAN subnet: Choose an IP address from the LAN subnet
   • Router 2:
     • Interface connecting to Router 1: 192.168.25.81/30
     • Interface connecting to LAN subnet: Choose an IP address from the LAN subnet

3. Assign IP addresses for LAN subnets based on the /28 subnetting:

   • LAN subnet 1: 192.168.25.0/28
     • Usable IP range: 192.168.25.1 - 192.168.25.14
     • Network address: 192.168.25.0
     • Broadcast address: 192.168.25.15
     • Default gateway for devices in LAN subnet 1: Router 1's LAN interface IP
   • LAN subnet 2: Next available /28 subnet
     • Repeat the above steps for subsequent LAN subnets

By assigning IP addresses and subnetting as described above, you should be able to connect the LANs to each other through the routers while maintaining the specified addressing plan. Make sure to configure routing between the routers to allow communication between the LANs.

[Joseph W. Doherty]

"LAN subnets will use /28, which gives you 16 hosts per subnet."

Actually 16 IPs, 14 hosts.

[Ruben Cocheno]

@claudemichel 

if both SVIs are on the same router/switch, you just need to make sure both ping the gateway repsectively and each has a default gateway on each one