Learn how to set up an internet connection using Cisco 1812J with clear instructions.
Start with basic network configuration to prepare for an AWS VPN environment.
Detailed steps make it beginner-friendly and easy to follow.
Background
Previously, we initialized the Cisco 1812J in the following article. Without a manual, we proceeded with trial and error and managed to complete the initialization. For those familiar with the process, it might be a quick task, but if you're interested, feel free to check it out.
However, just initializing the router does not immediately enable connection to AWS and VPN. To connect to AWS and VPN, the router must first have internet access. Our company uses NURO Hikari as the internet provider, so we need to ensure that the Cisco 1812J can connect to the internet through the NURO Hikari ONU.
To start, we connected the Cisco 1812J to the NURO Hikari ONU using a LAN cable. As expected, this alone was not sufficient to access the internet. After some research, we finally got it working, so we have documented the steps below.
Method
Building on the previous setup, the new configuration is as follows. Additionally, the fiber optic connection to the ONU has already been established, and the ONU itself is connected to the internet.
Laptop (Ubuntu Desktop 22.04 LTS)
VPN Router (Cisco 1812J)
USB RJ45 Console Cable
LAN Cable
NSD-G1000T (NURO Hikari ONU)
Checking the ONU
We will configure the ONU based on the following manual:
First, connect your laptop to the ONU using a LAN cable and access http://192.168.1.1. Log in with the username and the password found on the device label.
In the [LAN] section under [Information Display], you can check the ONU’s IP address. In [DHCP Lease], you can see the currently assigned IP addresses. For this setup, we will assign 192.168.1.254, which is not currently in use, to the Cisco 1812J.
Image
Connecting Cisco 1812J and Configuring the Router
First, identify the USB port of the serial cable and connect it to the Cisco 1812J.
guest@ubuntu:∼$ sudo dmesg | grep ttyUSB
[ 34.739950] usb 1-1.3.4: FTDI USB Serial Device converter now attached to ttyUSB0
[ 34.996889] usb 1-1.3.1: pl2303 converter now attached to ttyUSB1
guest@ubuntu:∼$ cu --speed 9600 --parity=none --line /dev/ttyUSB0
Connected.
Router1>
In User Mode (indicated by > at the prompt), only basic monitoring commands can be executed To configure the router, switch to Privileged Mode (indicated by # at the prompt) and then enter Global Configuration Mode (indicated by (config)#). This allows us to configure various router settings.
Router1> enable
Password: ciscoRouter1# conf t
Enter configuration commands, one per line. End with CNTL/Z.
Configuring the Loopback Interface The loopback interface is a virtual interface that can only communicate with the device itself (Cisco 1812J). We assign it the IP address 192.168.192.168.
Router1(config)# interface Loopback 0
*Apr 6 12:39:06.171: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback0, changed state to up
Router1(config-if)# ip address 192.168.192.168 255.255.255.0
Router1(config-if)# exit
Configuring the Interface Connected to the ONU We assign the IP address 192.168.1.254 to FastEthernet 0, which is connected to the ONU. This interface will be used to send traffic to the ONU and access the internet.
Router1(config)# interface FastEthernet 0
Router1(config-if)# ip address 192.168.1.254 255.255.255.0
Router1(config-if)# no shutdown
Router1(config-if)# exit
*Apr 6 12:42:33.035: %LINK-3-UPDOWN: Interface FastEthernet0, changed state to up
*Apr 6 12:42:45.419: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0, changed state to up
Configuring the Routing Information As a test, we will attempt to reach Google DNS (8.8.8.8) via the internet. To do this, we configure a route to forward traffic destined for 8.8.8.8 to the ONU (192.168.1.1).
Router1(config)# ip route 8.8.8.8 255.255.255.255 192.168.1.1
Router1(config)# exit
*Apr 6 12:44:39.887: %SYS-5-CONFIG_I: Configured from console by console
However, the route will not take effect immediately.
Router1# show ip route
Default gateway is not set
Host Gateway Last Use Total Uses Interface
ICMP redirect cache is empty
We must execute the ip routing command to apply the routing settings.
Router1# conf t
Enter configuration commands, one per line. End with CNTL/Z.
Router1(config)# ip routing
Router1(config)# exit
*Apr 6 12:45:53.867: %SYS-5-CONFIG_I: Configured from console by console
Router1# show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
C 192.168.192.0/24 is directly connected, Loopback0
8.0.0.0/32 is subnetted, 1 subnets
S 8.8.8.8 [1/0] via 192.168.1.1
C 192.168.1.0/24 is directly connected, FastEthernet0
C 192.168.101.0/24 is directly connected, FastEthernet1
Testing Network Connectivity Use the ping command to check connectivity to 8.8.8.8. If we receive !!!!!, it means that five ICMP requests were sent and all five received responses, confirming that the router can reach an internet IP address.
Router1# ping 8.8.8.8
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 8.8.8.8, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms
Now, Cisco 1812J can finally access the internet! Next time, we will connect it to AWS and VPN—finally returning to AWS-related tasks. I hope this guide will be helpful to others.
