08-17-2019 04:27 AM
I'm trying to setup my new home network with some cisco devices. I am new with configuration of business network devices, but I want to learn to work with them get more of this devices in my home. But I have basic problems with my Cisco C1111-8P since more than 2 weeks and I get no solution for it.
The Cisco Router is connected with the ETH 0/0/0 port (configured as WAN) to the router of my ISP. I get an IP address (192.168.1.11) from the ISP router and I think the router has access to the internet. When I connect my notebook to one of the LAN ports (ETH 1/0/6) my notebook gets an IP address (e.g. 10.19.14.10) of the defined DHCP pool from the Cisco router. But I cannot get internet access with my notebook.
This is my actual Cisco router configuration.
! ! Last configuration change at 22:37:58 UTC Mon Aug 12 2019 ! version 16.9 service config service timestamps debug datetime msec service timestamps log datetime msec platform qfp utilization monitor load 80 no platform punt-keepalive disable-kernel-core ! hostname NEXUS-1 ! boot-start-marker boot-end-marker ! ! enable secret 5 XXXXXXXX enable password XXXXXXXX ! no aaa new-model ! ip name-server 192.168.1.1 ip dhcp excluded-address 10.14.14.1 10.14.14.9 ip dhcp excluded-address 10.14.14.250 10.14.14.254 ip dhcp excluded-address 10.19.14.1 10.19.14.9 ip dhcp excluded-address 10.19.14.250 10.19.14.254 ip dhcp excluded-address 10.2.14.1 10.2.14.9 ip dhcp excluded-address 10.2.14.250 10.2.14.254 ! ip dhcp pool NEXNET network 10.14.14.0 255.255.255.0 default-router 10.14.14.1 dns-server 10.14.14.1 ! ip dhcp pool SkyNET network 10.19.14.0 255.255.255.0 default-router 10.19.14.1 dns-server 10.19.14.1 ! ip dhcp pool bitNET network 10.2.14.0 255.255.255.0 default-router 10.2.14.1 dns-server 10.2.14.1 ! ! ! ipv6 unicast-routing ! ! ! ! ! ! ! subscriber templating multilink bundle-name authenticated ! ! ! crypto pki trustpoint TP-self-signed-2759056948 enrollment selfsigned subject-name cn=IOS-Self-Signed-Certificate-2759056948 revocation-check none rsakeypair TP-self-signed-2759056948 ! ! crypto pki certificate chain TP-self-signed-2759056948 certificate self-signed 01 nvram:IOS-Self-Sig#5.cer ! license udi pid C1111-8P sn XXXXXXXX no license smart enable ! diagnostic bootup level minimal ! spanning-tree extend system-id ! ! username YYYYYYYY privilege 15 password 0 XXXXXXXX ! redundancy mode none ! ! vlan internal allocation policy ascending ! ! ! ! ! ! interface GigabitEthernet0/0/0 description Internet ip address dhcp negotiation auto ipv6 enable ipv6 nd autoconfig default-route ipv6 dhcp client request vendor ! interface GigabitEthernet0/0/1 description Intranet ip address dhcp negotiation auto ! interface GigabitEthernet0/1/0 description SkyNET switchport access vlan 200 ! interface GigabitEthernet0/1/1 description bitNET switchport access vlan 400 ! interface GigabitEthernet0/1/2 description SkyNET switchport access vlan 200 ! interface GigabitEthernet0/1/3 description bitNET switchport access vlan 400 ! interface GigabitEthernet0/1/4 description SkyNET switchport access vlan 200 ! interface GigabitEthernet0/1/5 description bitNET switchport access vlan 400 ! interface GigabitEthernet0/1/6 description SkyNET switchport access vlan 200 ! interface GigabitEthernet0/1/7 description bitNET switchport access vlan 400 ! interface Vlan1 no ip address ! interface Vlan100 description NEXNET ip address 10.14.14.1 255.255.255.0 ! interface Vlan200 description SkyNET ip address 10.19.14.1 255.255.255.0 ! interface Vlan400 description bitNET ip address 10.2.14.1 255.255.255.0 ! ip forward-protocol nd ip http server ip http authentication local ip http secure-server ip http client source-interface GigabitEthernet0/0/0 ip route 0.0.0.0 0.0.0.0 192.168.1.1 GigabitEthernet0/0/0 ! ! ! ! snmp-server community XXXXXXXX RO ! ! control-plane ! ! line con 0 transport input none stopbits 1 line vty 0 4 password XXXXXXXX login ! ntp server ip 0.de.pool.ntp.org prefer source GigabitEthernet0/0/0 ntp server 1.de.pool.ntp.org source GigabitEthernet0/0/0 ntp server 1.ciscosb.pool.ntp.org source GigabitEthernet0/0/0 ntp server ip 0.ciscosb.pool.ntp.org source GigabitEthernet0/0/0 ! ! ! ! ! end
Is there something wrong in my configuration Could anyone help me what is missing in my configuration to get it work?
Solved! Go to Solution.
08-17-2019 06:18 AM
Hello bition,
you are missing the configuration of NAT = Network Address Translation
Your internal IP addresses like 10.14.14.X are private IP addresses per RFC 1918 and you need to map them to the external interface IP address.
You need the following:
int gi0/0/0
ip nat outside
int vlan 100
ip nat inside
int vlan 200
ip nat inside
int vlan 400
ip nat inside
ip nat inside source list 11 interface gi0/0/0 overload
access-list 11 remark define internal networks
access-list 11 permit 10.14.14.0 0.0.0.255
access-list 11 permit 10.2.14.0 0.0.0.255
access-list 11 permit 10.19.14.0 0.0.0.255
Routing is not enough to provide internet access you need NAT.
Your default static route is fine and you don't need to change it.
>>
ip route 0.0.0.0 0.0.0.0 192.168.1.1 GigabitEthernet0/0/0
This is fine.
You need also to associate one L2 access interface to vlan 100 to be able to use SVI vlan 100.
To be noted also the ISP assigned is a private IP address and the ISP will perform NAT on its device too.
(unless you changed your public IP to this 192.168.1.1 for security reasons).
NAT is triggered when a packet needs to go from a NAT inside interface to a NAT outside interface.
Inter Vlan routing should still work correctly because all SVIs are configured with ip nat inside.
Hope to help
Giuseppe
08-17-2019 05:20 AM - edited 08-17-2019 05:23 AM
delete your default IP Route command
>Conf t
#no ip route 0.0.0.0 0.0.0.0 192.168.1.1 GigabitEthernet0/0/0
and try following command
#ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0/0
if this is also not working, then you should ask your ISP provider about the next hope IP address and replace the interface with next hope IP address
08-17-2019 06:28 AM
Hi Manish,
thank you for you quick response.
When I define the next hop with the address of the router fro my ISP, the Cisco router gets access to the internet. With your suggested configuration of the IP route without the next hop address, the Cisco router itself gets no connection to the internet.
To explain my current configuration I have createsome pictures for better understanding
I want to replace all the ASUS devices (green devices) behind the Telekom router (router rented from my ISP) and replace it with Cisco devices (blue devices).
I hope this helps to get a better understanding of my actual issue.
Greetings, bition
08-17-2019 06:39 AM
Hello Manish,
NAT is required as explained by Luis and me in other posts in this thread.
Your suggested change to the static default route requires that Proxy ARP is enabled on the the telekom router and would make an excessive use of ARP.
With a specified next-hop a router makes a single ARP request for the next-hop addess
Wth a static route ponting to a LA interface the router needs to make an ARP request for each destination on the internet !!!
This can cause the ARP table to grow too much.
Hope to help
Giuseppe
08-17-2019 06:16 AM
Hi @bition ,
In addition to the change indicated by manish.sharma@cjpl.in , I think you should configure NAT on your router:
int g0/0/0
ip nat outside
int vlan 100
ip nat inside
int vlan 200
ip nat inside
int vlan 400
ip nat inside
access-list 1 permit 10.2.14.0 0.0.0.255
access-list 1 permit 10.14.14.0 0.0.0.255
access-list 1 permit 10.19.14.0 0.0.0.255
ip nat inside source list 1 interface g0/0/0 overload
Regards
08-17-2019 06:18 AM
Hello bition,
you are missing the configuration of NAT = Network Address Translation
Your internal IP addresses like 10.14.14.X are private IP addresses per RFC 1918 and you need to map them to the external interface IP address.
You need the following:
int gi0/0/0
ip nat outside
int vlan 100
ip nat inside
int vlan 200
ip nat inside
int vlan 400
ip nat inside
ip nat inside source list 11 interface gi0/0/0 overload
access-list 11 remark define internal networks
access-list 11 permit 10.14.14.0 0.0.0.255
access-list 11 permit 10.2.14.0 0.0.0.255
access-list 11 permit 10.19.14.0 0.0.0.255
Routing is not enough to provide internet access you need NAT.
Your default static route is fine and you don't need to change it.
>>
ip route 0.0.0.0 0.0.0.0 192.168.1.1 GigabitEthernet0/0/0
This is fine.
You need also to associate one L2 access interface to vlan 100 to be able to use SVI vlan 100.
To be noted also the ISP assigned is a private IP address and the ISP will perform NAT on its device too.
(unless you changed your public IP to this 192.168.1.1 for security reasons).
NAT is triggered when a packet needs to go from a NAT inside interface to a NAT outside interface.
Inter Vlan routing should still work correctly because all SVIs are configured with ip nat inside.
Hope to help
Giuseppe
08-17-2019 06:44 AM
Thank you Guiseppe and thank you Lius!
This is the solution I am looking for more than two weeks. Now my configuration works.
Now I can understand the required configuration and try some more setting without any pressure of time.
Greetings, bition
08-17-2019 06:50 AM
Hello bition,
you are wellcome and we are glad to be of help
Best Regards
Giuseppe
08-17-2019 07:02 AM
apologize that I missed pointing the Nat commands which is essential as already stated.
However, I do not think that you need interface number after you have already defined next hope iP address
IP route 0.0.0.0 0.0.0.0 <next hope IP address>
After that I think we can define metric etc but not the interface number, if yes what is the use as above statement as it tells that if you wanted to go anywhere except local landing go to next hope device IP address, we do not define next HOPe IP address as well as next HOPE interface number as generally that is not available to us in case of ADSL is being as bridge mode.
Correct if I am wrong.
08-17-2019 07:27 AM
Hello Manish,
no problem I just wanted to point out that a static route referring only a LAN interface is not a good idea for the need of Proxy ARP enabled on the other device and for the increased ARP activity.
Yes the configuration of an ip route with a next-hop is enough to avoid described issues with Proxy ARP.
The use of both an IP next-hop and an outgoing interface has been added in the context of VRFs, where it is used.
The command with both options should be accepted even if the outgoing interface in this case is a redundant not necessary parameter.
An ADSL router acting as a bridge does not perform IP routing so no need to configure a default static route in this case
Hope to help
Giuseppe
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