12-12-2023 09:32 AM
Hello
A year further into exploring networks, and after creating multiple packet tracers, I've encountered a difficulty again.
I'm currently working on an exercise where I need to set up complete networks for two offices that will eventually be connected via VPN. This is currently working well.
Here's an explanation of the setup and the problem.
Office A with an internal IP range of 10.19.0.0/16.
The setup is as follows: the access switches are connected to 2 Layer 3 switches responsible for internal routing (via OSPF). There is an EtherChannel and HSRP active between the Layer 3 switches.
The Layer 3 switches are mesh-connected to 2 routers (Main and backup). These 2 routers are both connected to ISP 1 and 2 for complete redundancy. The ISPs are connected to an external webserver.
Router main to ISP 1: 83.0.19.2 -> 83.0.19.1/30 Router main to ISP 2: 63.0.19.2 -> 63.0.19.1/30
Router backup to ISP 1: 83.0.19.6 -> 83.0.19.5/30 Router backup to ISP 2: 63.0.19.6 -> 63.0.19.5/30
NAT is active on both interfaces of both routers.
However, when I disable the interfaces of router main and one of router backup to test redundancy, nothing happens. I can't browse the webserver.
A traceroute also shows that it's not working.
Can you please guide me on where the issue might be?
Kind regards
M.
Config devices:
Router-main
interface GigabitEthernet0/0/1
ip address 10.19.40.2 255.255.255.252
ip ospf priority 10
ip access-group WEB in
ip access-group estab out
ip nat inside
duplex auto
speed auto
!
interface GigabitEthernet0/0/2
ip address 10.19.40.14 255.255.255.252
ip ospf priority 10
ip access-group WEB in
ip access-group estab out
ip nat inside
duplex auto
speed auto
router ospf 2
router-id 3.3.3.3
log-adjacency-changes
network 10.19.40.0 0.0.0.3 area 1
network 10.19.40.12 0.0.0.3 area 1
network 10.19.100.8 0.0.0.3 area 1
network 83.0.19.0 0.0.0.3 area 0
network 63.0.19.0 0.0.0.3 area 0
default-information originate
!
ip nat pool EDP 63.0.19.2 63.0.19.2 netmask 255.255.255.252
ip nat pool TELENET 83.0.19.2 83.0.19.2 netmask 255.255.255.252
ip nat inside source list 1 pool TELENET overload
ip nat inside source list 2 pool EDP overload
ip classless
ip route 0.0.0.0 0.0.0.0 83.0.19.1
ip route 0.0.0.0 0.0.0.0 63.0.19.1 200
!
ip flow-export version 9
!
!
access-list 1 permit 10.19.0.0 0.0.255.255
access-list 2 permit 10.19.0.0 0.0.255.255
ip access-list extended WEB
permit icmp any any
permit ospf any any
permit tcp 10.19.0.0 0.0.255.255 any eq 443
permit tcp 10.19.0.0 0.0.255.255 any eq www
ip access-list extended estab
permit icmp any any
permit ospf any any
permit tcp any 10.19.0.0 0.0.255.255 established
Router-backup
interface Loopback1
ip address 10.19.100.13 255.255.255.252
!
interface GigabitEthernet0/0/0
no ip address
duplex auto
speed auto
shutdown
!
interface GigabitEthernet0/0/1
ip address 10.19.40.6 255.255.255.252
ip ospf priority 5
ip access-group WEB in
ip access-group estab out
ip nat inside
duplex auto
speed auto
!
interface GigabitEthernet0/0/2
ip address 10.19.40.10 255.255.255.252
ip ospf priority 5
ip access-group WEB in
ip access-group estab out
ip nat inside
duplex auto
speed auto
!
interface Serial0/1/0
no ip address
ip nat outside
clock rate 2000000
shutdown
!
interface Serial0/1/1
no ip address
ip nat outside
clock rate 2000000
shutdown
!
interface Serial0/2/0
ip address 83.0.19.6 255.255.255.252
ip ospf cost 5
ip ospf priority 10
ip nat outside
clock rate 2000000
shutdown
!
interface Serial0/2/1
ip address 63.0.19.6 255.255.255.252
ip ospf cost 10
ip ospf priority 5
ip nat outside
!
router ospf 2
router-id 4.4.4.4
log-adjacency-changes
network 10.19.40.4 0.0.0.3 area 1
network 10.19.40.8 0.0.0.3 area 1
network 10.19.100.12 0.0.0.3 area 1
network 63.0.19.4 0.0.0.3 area 0
network 83.0.19.4 0.0.0.3 area 0
default-information originate
!
ip nat pool EDP 63.0.19.6 63.0.19.6 netmask 255.255.255.252
ip nat pool TELENET 83.0.19.6 83.0.19.6 netmask 255.255.255.252
ip nat inside source list 1 pool TELENET overload
ip nat inside source list 2 pool EDP overload
ip classless
ip route 0.0.0.0 0.0.0.0 83.0.19.5
ip route 0.0.0.0 0.0.0.0 63.0.19.5 200
!
ip flow-export version 9
!
!
access-list 1 permit 10.19.0.0 0.0.255.255
access-list 2 permit 10.19.0.0 0.0.255.255
ip access-list extended WEB
permit icmp any any
permit ospf any any
permit tcp 10.19.0.0 0.0.255.255 any eq 443
permit tcp 10.19.0.0 0.0.255.255 any eq www
ip access-list extended estab
permit icmp any any
permit ospf any any
permit tcp any 10.19.0.0 0.0.255.255 established
12-12-2023 12:03 PM
Hi @9K , I try help to you, it appears that the issue revolves around redundancy testing, specifically when disabling interfaces on the main router and one of the backup routers. Even though redundancy measures, such as HSRP and EtherChannel, have been implemented, browsing the webserver fails during these tests. To troubleshoot this, you may want to ensure that the HSRP state transitions are seamless and that the routing protocols, in this case, OSPF, are properly handling the changes. Additionally, reviewing the NAT configurations on the routers, especially during failover scenarios, is crucial to maintaining connectivity to external resources. Investigating any potential access list or routing discrepancies that may arise during the transition between routers could provide insights into resolving the issue and ensuring a smooth redundancy setup for the interconnected offices.
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