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Connecting Cisco 2911 into internet through ISP's router

juhaniheino
Level 1
Level 1

Good evening

I recently got almost brand new Cisco 2911 router and Cisco 2960 switch for free from school. I've been configuring both a little bit in school so I can handle the basic stuff. I currently live in an older apartment where a coaxial cable comes into ISP's provided router. The router also happens to be a Cisco device (Cisco EPC3825). This router is wireless with four ethernet ports. Now, 2911 does not have a coaxial input so I have to put ISP's router before Cisco 2911 in my setup. This setup will be a temporary one and I am just testing how things work out. I am moving sooner to a newer apartment where there will be ethernet ports in the walls so I can move my ISP's router behind 2911.

I know my public IP address and ISP's provided gateway and DNS-servers. Currently ISP's router's LAN IP is 192.168.1.1. I connected from first ethernet port of the ISP's router into 2911's GigabitEthernet0/0 port. I gave an IP address of 192.168.1.2 to the 2911's 0/0 port. From GigabitEthernet0/1 goes ethernet cable into my 2960 switch and from there on it goes to my desktop machine and server machine. In the future I connect the ISP's router into the 2960. Currently I haven't made any changes into ISP's router's settings. They are pretty much factory defaults.

The network I have given to my LAN devices behind 2911 is 172.17.1.0/24. The 2911's 0/1 port has IP address of 172.17.1.1. The 2960 switch has IP address of 172.17.1.2. I installed a DHCP server on the 2911 router and when I connect my laptop into the switch it gives me an IP address from 172.17.1.10-172.17.1.250 area. Now I can ping from laptop the 2960 switch, 2911 router's both ports and the ISP's router. But then I cannot ping google's public DNS (8.8.8.8) nor ISP's provided gateway for example. I have desktop computer plugged straight into ISP's router, and internet works very well from there. Also if I connect my laptop via wireless into the ISP's router, internet works very well. But from either setup (desktop into ISP router or laptop via wireless into ISP router) I can only ping Cisco 2911's 0/0 port but not behind that. From the 2911 itself I cannot ping to either laptop nor desktop machine even when they have their firewalls off.

Here is the config of the 2911 router:

    Current configuration : 1528 bytes
    !
    version 15.4
    service timestamps debug datetime msec
    service timestamps log datetime msec
    service password-encryption
    !
    hostname Router
    !
    boot-start-marker
    boot-end-marker
    !
    !
    !
    no aaa new-model
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    ip dhcp excluded-address 172.17.1.1 172.17.1.10
    !
    ip dhcp pool LAN_POOL
     network 172.17.1.0 255.255.255.0
     default-router 172.17.1.1
     dns-server 8.8.8.8 8.8.4.4
     lease 7
    !
    !
    !
    ip cef
    no ipv6 cef
    multilink bundle-name authenticated
    !
    !
    cts logging verbose
    !
    !
    !
    !
    !
    redundancy
    !
    !
    !
    !
    !
    !
    interface Embedded-Service-Engine0/0
     no ip address
     shutdown
    !
    interface GigabitEthernet0/0
     ip address 192.168.1.2 255.255.255.0
     ip nat outside
     ip virtual-reassembly in
     duplex auto
     speed auto
    !
    interface GigabitEthernet0/1
     ip address 172.17.1.1 255.255.255.0
     ip nat inside
     ip virtual-reassembly in
     duplex auto
     speed auto
    !
    interface GigabitEthernet0/2
     no ip address
     shutdown
     duplex auto
     speed auto
    !
    ip forward-protocol nd
    !
    no ip http server
    no ip http secure-server
    !
    ip nat inside source list 23 interface GigabitEthernet0/0 overload
    ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0
    !
    !
    !
    access-list 23 permit 172.17.1.0 0.0.0.25
    !
    control-plane
    !
    !
    !
    line con 0
     password 7 091D1C5A4A11141E
     login
    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
     password 7 0257560858120C2D
     login
     transport input none
    !
    scheduler allocate 20000 1000
    !
    end

As you can see from the configs I have tried to add static routing and playing with the NAT, neither one giving any results. What I am trying to achieve here is to connect to internet behind 2911 router, and to connect from internet to my server machine behind 2911 router. The solution may be simple but I just can't see it. Thanks in advance.

Regards

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