02-15-2010 03:20 PM - edited 03-04-2019 07:31 AM
Hi,
This is my setup:
netopia modem connects my DSL via PPPoE (so my modem handles authentication and assigns the 5 static IPs that my ISP gave me).
I want to setup my CISCO 1812 router to handle the connection and route the traffic to the other ports which I will have computers attached to.
I basically need help setting up the FastEthernet0 (Public static IP) port to handle the connection from the netopia modem. Then have the FE0 port to give a private IP Vlan 1 (192.168.1.1-192.168.1.254) to all the other ports FE2-9 via dhcp server. I do not know how to do this.
Thanks
02-16-2010 08:59 AM
Hello Roshan,
first of all you need to understand how the modem assigns ip address.
If it uses DHCP and fas0/0 is your external interface
int fas0/0
ip address dhcp
ip nat outside
int fas0/1
ip address 192.168.11.1 255.255.255.0
ip nat inside
Or if you have an etherswitch module:
int fas0/1
no ip addr
shut
int vlan 1
ip address 192.168.1.1 255.255.255.0
ip nat inside
! explicit enable needed here
no shut
!
this allows you to connect devices to etherswitch ports that are associated to vlan1 by default
ip route 0.0.0.0 0.0.0.0 fas0/0 dhcp
access-list 11 permit 192.168.1.0 0.0.0.255
ip nat inside source list 11 interface fas0/0 overload
a local DHCP pool can be configured using following commands
ip dhcp excluded-address 192.168.1.1
!
ip dhcp pool DATI
network 192.168.1.0 255.255.255.0
default-router 192.168.1.1
dns-server 192.168.1.1
lease 0 1
note:
if the modem doesn't assign ip address you need to configure it manually on the fas0/0 interface
Hope to help
Giuseppe
02-16-2010 10:11 AM
Hi,
My modem does not assign it dhcp. Can you tell me the full configuration. If the public ip is 11.11.11.11.
02-16-2010 12:32 PM
Hello Roshan84,
I report here only the changes from the previous post
int fas0/0
! adjust for the correct subnet mask
ip address 11.11.11.11 255.255.255.248
ip nat outside
the default route becomes
ip route 0.0.0.0 0.0.0.0 11.11.11.x
if you know what is the ip address of your default gateway
or
ip route 0.0.0.0 0.0.0 fas0/0
Note:
you should also configure the dns servers provided by your ISP using
ip name-server y.y.y.y
Hope to help
Giuseppe
02-16-2010 12:38 PM
ip route 0.0.0.0 0.0.0 fas0/0
By any means, avoid that. It cause router to ARP for every destination and cause performances to degrade unacceptably.
02-16-2010 02:29 PM
Hello Paolo,
thanks for your correction.
rated as it deserves.
Best Regards
Giuseppe
02-16-2010 02:30 PM
I'm confused so can you post exactly what I need to do for the config
02-16-2010 02:35 PM
Hello Roshan,
use all the info in my first post and the following updated info:
report here only the changes from the previous post
ip routing
int fas0/0
! adjust for the correct subnet mask
ip address 11.11.11.11 255.255.255.248
ip nat outside
the default route becomes
ip route 0.0.0.0 0.0.0.0 11.11.11.x
note1 : you need to know what is the ip address of your default gateway
Note2:
you should also configure the dns servers provided by your ISP using
ip name-server y.y.y.y
where y.y.y.y is the DNS server IP address
Hope to help
Giuseppe
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