# Lab 9 - Multiarea OSPF & GRE

Shrimp Co. is opening remote offices in Milwaukee and New Orleans. Implement multi-area OSPF for scalable routing and configure GRE tunnels to connect all locations over the internet.

Tip: Individual topology files are available in the diagrams folder on my Github

# Configuration Tasks

# 1. Access Layer Configuration:

Host access ports
- Configure according to diagram
- Add descriptions
Management SVIs
- Configure VLAN 99 SVIs according to diagram
VLANs, Trunks & Port-channels
- Ensure VLAN databases are matching and VLANs are allowed across all links

# 2. Distribution Layer Configuration:

Routed Ports & Loopback0
- Configure routed ports and Loopback0 according to diagram
VLANs, Trunks & Port-channels
- Ensure VLAN databases are matching and VLANs are allowed across all links
VRRP Configuration
- Configure VIPs according to diagram
- Load balance active gateways using priority
- Implement MD5 authentication
OSPF
- Configure OSPF process 1 with passive-interface default
- Advertise all host subnets with a single summary network statement
- Advertise Loopback0
- Form adjacencies on Eth5-6 in Area 0
- Utilize MD5 neighbor authentication

# 3. Router Configuration:

Routed Ports & Loopback0
- Configure routed ports, Loopback0, and Tunnel0 according to diagram
OSPF
- Configure OSPF process 1 with passive-interface default
- Form adjacencies on Eth0/1-2 in Area 0
- Form adjacency on Tunnel0 in Area 1 on sea-mdf-r1
- Form adjacency on Tunnel0 in Area 2 on sea-mdf-r1
- Originate a default route
- Advertise Loopback0
BGP
- Peer BGP using a neighbor statement targeting your public next-hop
NAT
- Allow internet access for only host subnets by configuring NAT overload
DHCP
Configure DHCP Pools on both routers for all host subnets so that routers cannot provide overlapping IP addresses

# 4. Remote Site Configuration:

Switch
- Ensure VLAN 10 is stretched up to router subinterface
Router
- Configure router subinterface and Loopback0 according to diagram
- Configure static default route to public next-hop
- Configure OSPF process 1 with passive-interface default
- Form adjacency on Tunnel0 in Area 1 on sea-mdf-r1
- Form adjacency on Tunnel0 in Area 2 on sea-mdf-r1
- Configure static NAT for local host for internet reachability

# Success Criteria

Hosts at HQ have ping reachability to remote sites
Hosts at HQ can curl http://seamart.com
Pings to the internet fail for Loopbacks but not hosts

Encrypt WAN traffic on your GRE tunnels using IPsec tunnel protection
Configure Area 1 and Area 2 as totally stub areas
Configure a route-map that matches a prefix-list inbound to your BGP peers which allows you to learn ONLY the default route

# Verification Commands

show ip ospf neighbor
show ip route ospf
show interfaces tunnel0

show ip bgp summary
show ip bgp

# Questions to Explore

Cisco Press - BGP Fundamentals IP Routing: OSPF Configuration Guide EOS OSPF Guide How to configure GRE Tunnel in CISCO Router How to configure GRE over IPSec in Cisco IOS and Cisco IOS-XE devices