1841 - no outside connection

[sp0000003]

I've got a (lab) 1841 router, that wont connect to the outside(internet)

Cannot ping 8.8.8.8 from router

My config is

Current configuration : 1005 bytes

!

version 12.4

service config

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname Cisco1841

!

boot-start-marker

boot-end-marker

!

! card type command needed for slot 0

no logging console

!

no aaa new-model

!

resource policy

!

mmi polling-interval 60

no mmi auto-configure

no mmi pvc

mmi snmp-timeout 180

ip subnet-zero

ip cef

!

!

no ip dhcp use vrf connected

!

!

no ip domain lookup

!

!

!

!

interface FastEthernet0/0

ip address dhcp

ip nat outside

duplex auto

speed auto

!

interface FastEthernet0/1

ip address 192.168.0.1 255.255.255.0

ip nat inside

duplex auto

speed auto

!

ip classless

ip route 0.0.0.0 0.0.0.0 FastEthernet0/0

!

ip http server

ip nat inside source list 10 interface FastEthernet0/0 overload

!

access-list 10 permit 192.168.0.0 0.0.0.255

!

control-plane

!

!

line con 0

line aux 0

line vty 0 4

login

!

end

####################3

Cisco1841(config)# do sho ip int br

Interface                  IP-Address      OK? Method Status                Protocol

FastEthernet0/0            10.111.131.253  YES DHCP   up                    up 

FastEthernet0/1            192.168.0.1     YES manual up                    down

NVI0                       unassigned      YES unset  up                    up

Thanks

[Reza Sharifi]

Why is interface fa0/1 down?

Is there anything connected to this interface?

[Richard Burts · Accepted solution]

I suspect that the issue has to do with the static default route.

ip route 0.0.0.0 0.0.0.0 FastEthernet0/0

When you configure a static route pointed at an Ethernet interface it requires that the next hop router has enabled proxy arp. And increasingly providers are not enabling proxy arp (because of the security implications). I suggest that you change your static default route to this and tell us if it works better.

ip route 0.0.0.0 0.0.0.0 dhcp

HTH

Rick

[sp0000003]

Nothing is connected to fa0/1, cause I havn't connected my pc (but it works)

Will try the new static route, later to day, but what is the difference between

ip route x.x.x.x x.x.x.x interface

and

ip route x.x.x.x x.x.x.x dhcp

[cadet alain · Accepted solution]

Hi,

As Richard already explained a static route pointing out a multipoint ethernet interface cannot work if the next-hop is not implementing proxy-arp because the router will arp for the destination address instead of the next-hop address believing it is located out the multipoint interface and if the nexst-hop is implementing proxy-arp AND knows about the destination then it will reply on its behalf.

ip route 0.0.0.0 0.0.0.0 will set the next-hop as the default-router advertised by DHCP and will set the AD to 1 but this is not mandatory to explicitly configure a static route in this case as the router should install one automatically to the default-router IP with an AD of 254.

Regards

Alain

Don't forget to rate helpful posts.

[sp0000003]

Thanks a million

[Richard Burts]

I am glad that our responses provided an explanation of your problem. Thank you for using the rating system to mark this question as answered. It makes the forum more useful when people can read about a problem and can know that a solution was found. Your marking has contributed to this process.

HTH

Rick