CISCO881-K9 router config

[bikky_jsr]

Hi

I have Cisco 881 router. Need to configure BSNL Leased Line. I have WAN IP 172.24.X.X/30 and Public IP 117.242.X.X/28. Along with this I wish to use private IP 192.168.0.0/24. Please suggest with configuration details.

[Georg Pauwen]

Hello,

here is what the config would look like. Not sure what you mean with public IP and WAN IP, you need to configure a public IP on FastEthernet4, I have used the 117.242.x.x address.

ip dhcp excluded-address 192.168.0.1
!
ip dhcp pool vlan1
network 192.168.0.0 255.255.255.0
default-router 192.168.0.1
dns-server 8.8.8.8 8.8.4.4
!
interface vlan 1
ip address 192.168.0.1 255.255.255.0
ip nat inside
!
interface FastEthernet0
!
interface FastEthernet1
!
interface FastEthernet2
!
interface FastEthernet3
!
interface FastEthernet 4
ip address 117.242.x.x 255.255.255.240
ip nat outside
!
ip nat inside source list 1 interface fastethernet4 overload
access-list 1 permit 192.168.1.0 0.0.0.255

ip route 0.0.0.0 0.0.0.0 Fastethernet4

[bikky_jsr]

Hi Georg,

Thanks for your reply. What I got from ISP is ome WAN IP in /30 and 14 public IP in /28 for LAN. LAN IPs has to be routed through WAN IP. It means fe4 should be using 172.24.x.x IP. 

Please suggest further.

Thanks again for your time and consideration.

[Georg Pauwen]

Hello,

understood. So in this case, the config would be:

ip dhcp excluded-address 192.168.0.1
!
ip dhcp pool vlan1
network 192.168.0.0 255.255.255.0
default-router 192.168.0.1
dns-server 8.8.8.8 8.8.4.4
!
interface vlan 1
ip address 192.168.0.1 255.255.255.0
ip nat inside
!
interface FastEthernet0
!
interface FastEthernet1
!
interface FastEthernet2
!
interface FastEthernet3
!
interface FastEthernet 4
ip address 172.24.x.x 255.255.255.252
ip nat outside
!
ip nat pool ISP 117.242.x.x 117.242.y.y netmask 255.255.255.240
ip nat inside source list 1 pool ISP overload
access-list 1 permit 192.168.1.0 0.0.0.255

ip route 0.0.0.0 0.0.0.0 Fastethernet4

In the pool, the x.x. is the start address, and the y.y. is the end address of the 117.242 range assigned to you by your provider.

[bikky_jsr]

Hello Georg,

Once again, thanks for your reply.

Let me explain my situation once again. My ISP says I must be using Public IPs provided 117.242.158.X/28 to get internet. I m bit confused about these two. I had already mentioned the wan IP 172.24.X.113 (gateway 172.24.X.114) and public IP 117.242.X.240/28. I have Cisco 881 K9 router. My ISP says, I wont be getting internet on WAN IP (Confused)... ISP says, I must be using provided public IP to get internet. Can you plz elaborate for my understanding?  Plz guide me, how can I configure my router. On which port I must configure the WAN IP (172.24.X.113) and the port where I should configure the LAN Public IP (117.242.X.241)

[Georg Pauwen]

Hello,

try the config below:

ip dhcp excluded-address 192.168.0.1
!
ip dhcp pool vlan1
network 192.168.0.0 255.255.255.0
default-router 192.168.0.1
dns-server 8.8.8.8 8.8.4.4
!
interface vlan 1
ip address 192.168.0.1 255.255.255.0
ip nat inside
!
interface FastEthernet0
!
interface FastEthernet1
!
interface FastEthernet2
!
interface FastEthernet3
!
interface FastEthernet 4
ip address 117.242.x.241 255.255.255.240
ip nat outside
!
ip nat inside source list 1 interface FastEthernet4 overload
access-list 1 permit 192.168.1.0 0.0.0.255

ip route 0.0.0.0 0.0.0.0 Fastethernet4