How Connect Cisco 1900 Router to ISP (Home Network)

[IT1Andy]

Hello! I am currently using Spectrum as my home internet provider. I am trying to do labs and get my CISCO 1900 Router connected to the network. I am having issues trying to get it working. I did a ipconfig on my home computer and this is the information I got. 

Wireless LAN adapter Wi-Fi:

Connection-specific DNS Suffix . : home
IPv6 Address. . . . . . . . . . . : 2600:6c58:4300:7734::92e
IPv6 Address. . . . . . . . . . . : 2600:6c58:4300:7734:65e2:3f7:5be6:8f98
Temporary IPv6 Address. . . . . . : 2600:6c58:4300:7734:9cf9:8d1f:9787:dccb
Temporary IPv6 Address. . . . . . : 2600:6c58:4300:7734:f97c:2ef7:c3f3:8b10
Link-local IPv6 Address . . . . . : fe80::65e2:3f7:5be6:8f98%10
IPv4 Address. . . . . . . . . . . : 192.168.1.11
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : fe80::4ad2:4fff:fef5:6d5a%10
192.168.1.1

I am not sure what I am supposed to use as my default gateway, or what should I get as the IP range on my Cisco router.

[Abzal]

H @IT1Andy 

Log in to your router and do command:

sh run

Then we can see what's wrong and help you.

[IT1Andy]

Building configuration...

Current configuration : 1323 bytes
!
! Last configuration change at 04:28:33 UTC Mon Apr 27 2020
!
version 15.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router1
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
!
!
!
!
!
!
!
!
!
!
!
!
ip dhcp pool lan\
network 192.168.2.0 255.255.255.0
dns-server 8.8.8.8
!
!
!
ip cef
no ipv6 cef
multilink bundle-name authenticated
!
cts logging verbose
!
!
license udi pid CISCO1941/K9 sn FJC1944E5WQ
!
!
!
redundancy
!
!
!
!
!
!
interface Embedded-Service-Engine0/0
no ip address
shutdown
!
interface GigabitEthernet0/0
ip address dhcp
ip nat outside
ip virtual-reassembly in
duplex auto
speed auto
!
interface GigabitEthernet0/1
ip address 192.168.2.1 255.255.255.0
ip nat inside
ip virtual-reassembly in
duplex auto
speed auto
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
ip nat source list 1 interface GigabitEthernet0/0 overload
ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0
!
!
!
access-list 1 permit 192.168.2.0 0.0.0.255
!
control-plane
!
!
!
line con 0
line aux 0
line 2
no activation-character
no exec
transport preferred none
transport output pad telnet rlogin lapb-ta mop udptn v120 ssh
stopbits 1
line vty 0 4
login
transport input none
!
scheduler allocate 20000 1000
!
end

Router1#
*Apr 27 04:37:31.399: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up
*Apr 27 04:37:32.399: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up
*Apr 27 04:37:38.391: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to down
*Apr 27 04:37:39.391: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to down
*Apr 27 04:37:46.391: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up
*Apr 27 04:37:47.391: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up
Router1#
Router1#show run
Building configuration...

Current configuration : 1323 bytes
!
! Last configuration change at 04:28:33 UTC Mon Apr 27 2020
!
version 15.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router1
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
!
!
!
!
!
!
!
!
!
!
!
!
ip dhcp pool lan\
network 192.168.2.0 255.255.255.0
dns-server 8.8.8.8
!
!
!
ip cef
no ipv6 cef
multilink bundle-name authenticated
!
cts logging verbose
!
!
license udi pid CISCO1941/K9 sn FJC1944E5WQ
!
!
!
redundancy
!
!
!
!
!
!
interface Embedded-Service-Engine0/0
no ip address
shutdown
!
interface GigabitEthernet0/0
ip address dhcp
ip nat outside
ip virtual-reassembly in
duplex auto
speed auto
!
interface GigabitEthernet0/1
ip address 192.168.2.1 255.255.255.0
ip nat inside
ip virtual-reassembly in
duplex auto
speed auto
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
ip nat source list 1 interface GigabitEthernet0/0 overload
ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0
!
!
!
access-list 1 permit 192.168.2.0 0.0.0.255
!
control-plane
!
!
!
line con 0
line aux 0
line 2
no activation-character
no exec
transport preferred none
transport output pad telnet rlogin lapb-ta mop udptn v120 ssh
stopbits 1
line vty 0 4
login
transport input none
!
scheduler allocate 20000 1000
!
end

[luis_cordova · Accepted solution]

Hi @IT1Andy 

Try this:

ip dhcp pool lan

network 192.168.2.0 255.255.255.0

default-router 192.168.2.1

dns-server 8.8.8.8

int g0/0 <~ to Spectrum 

ip add dhcp

no shut 

ip nat outside

exit

int g0/1 <- to LAN

ip add 192.168.2.1 255.255.255.0

no shut 

ip nat inside

exit

ip route 0.0.0.0 0.0.0.0 g0/0

access-list 1 permit 192.168.2.0 0.0.0.255

ip nat inside source list 1 interface g0/0 overload

Regards

[Richard Burts]

There has been a recent discussion in this community about the issue of static default routes which specify an outbound interface but not specify a next hop. And the same issue appears in this discussion. I would like to say again that while a static route (default route or other route) pointing to an outbound interface (especially if it is an Ethernet interface) but not specifying a next hop address may work it is also possible that it will not work at all (depending on whether the next hop supports proxy arp or does not support it). And even if it does work it is a sub optimal solution. When the outbound interface is Ethernet it is much better to specify a next hop address. Or in cases such as this post where the outbound interface is assigned dynamically and it might be difficult to know what next hop address to use it works to have the static default route configured like this

ip route 0.0.0.0 0.0.0.0 dhcp

[IT1Andy]

I updated the router with the information listed, but I am still not getting any connection. I have included the Show run information.

Building configuration...

Current configuration : 1323 bytes
!
! Last configuration change at 04:28:33 UTC Mon Apr 27 2020
!
version 15.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router1
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
!
!
!
!
!
!
!
!
!
!
!
!
ip dhcp pool lan\
network 192.168.2.0 255.255.255.0
dns-server 8.8.8.8
!
!
!
ip cef
no ipv6 cef
multilink bundle-name authenticated
!
cts logging verbose
!
!
license udi pid CISCO1941/K9 sn FJC1944E5WQ
!
!
!
redundancy
!
!
!
!
!
!
interface Embedded-Service-Engine0/0
no ip address
shutdown
!
interface GigabitEthernet0/0
ip address dhcp
ip nat outside
ip virtual-reassembly in
duplex auto
speed auto
!
interface GigabitEthernet0/1
ip address 192.168.2.1 255.255.255.0
ip nat inside
ip virtual-reassembly in
duplex auto
speed auto
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
ip nat source list 1 interface GigabitEthernet0/0 overload
ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0
!
!
!
access-list 1 permit 192.168.2.0 0.0.0.255
!
control-plane
!
!
!
line con 0
line aux 0
line 2
no activation-character
no exec
transport preferred none
transport output pad telnet rlogin lapb-ta mop udptn v120 ssh
stopbits 1
line vty 0 4
login
transport input none
!
scheduler allocate 20000 1000
!
end

Router1#
*Apr 27 04:37:31.399: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up
*Apr 27 04:37:32.399: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up
*Apr 27 04:37:38.391: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to down
*Apr 27 04:37:39.391: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to down
*Apr 27 04:37:46.391: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up
*Apr 27 04:37:47.391: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up
Router1#
Router1#show run
Building configuration...

Current configuration : 1323 bytes
!
! Last configuration change at 04:28:33 UTC Mon Apr 27 2020
!
version 15.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router1
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
!
!
!
!
!
!
!
!
!
!
!
!
ip dhcp pool lan\
network 192.168.2.0 255.255.255.0
dns-server 8.8.8.8
!
!
!
ip cef
no ipv6 cef
multilink bundle-name authenticated
!
cts logging verbose
!
!
license udi pid CISCO1941/K9 sn FJC1944E5WQ
!
!
!
redundancy
!
!
!
!
!
!
interface Embedded-Service-Engine0/0
no ip address
shutdown
!
interface GigabitEthernet0/0
ip address dhcp
ip nat outside
ip virtual-reassembly in
duplex auto
speed auto
!
interface GigabitEthernet0/1
ip address 192.168.2.1 255.255.255.0
ip nat inside
ip virtual-reassembly in
duplex auto
speed auto
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
ip nat source list 1 interface GigabitEthernet0/0 overload
ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0
!
!
!
access-list 1 permit 192.168.2.0 0.0.0.255
!
control-plane
!
!
!
line con 0
line aux 0
line 2
no activation-character
no exec
transport preferred none
transport output pad telnet rlogin lapb-ta mop udptn v120 ssh
stopbits 1
line vty 0 4
login
transport input none
!
scheduler allocate 20000 1000
!
end

[Georg Pauwen · Accepted solution]

Hello,

make sure the lines marked in bold match your configuration exactly:

version 15.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router1
!
boot-start-marker
boot-end-marker
!
no aaa new-model
!
--> ip dhcp excluded-address 192.168.2.1
!
ip dhcp pool lan\
network 192.168.2.0 255.255.255.0
--> default-router 192.168.2.1
dns-server 8.8.8.8
!
ip cef
no ipv6 cef
multilink bundle-name authenticated
!
cts logging verbose
!
license udi pid CISCO1941/K9 sn FJC1944E5WQ
!
redundancy
!
interface Embedded-Service-Engine0/0
no ip address
shutdown
!
interface GigabitEthernet0/0
ip address dhcp
ip nat outside
ip virtual-reassembly in
duplex auto
speed auto
!
interface GigabitEthernet0/1
ip address 192.168.2.1 255.255.255.0
ip nat inside
ip virtual-reassembly in
duplex auto
speed auto
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
--> ip nat inside source list 1 interface GigabitEthernet0/0 overload
--> ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0 dhcp
!
access-list 1 permit 192.168.2.0 0.0.0.255
!
control-plane
!
line con 0
line aux 0
line 2
no activation-character
no exec
transport preferred none
transport output pad telnet rlogin lapb-ta mop udptn v120 ssh
stopbits 1
line vty 0 4
login
transport input none
!
scheduler allocate 20000 1000
!
end