Cisco 881 Routing problem

rrangelov · ‎08-23-2011

Dear all, I have some problems with routing configuration on Cisco 881 router. Here is the story. I need the router to be able to root only two networks. The first one is the ISP network (192.168.4.0) and the second one is my private network (192.168.100.0).

I am able to ping 192.168.100.1 from my PC (192.168.100.5)

I am able to ping 192.168.4.100 from my PC (192.168.100.5)

I am able to ping 192.168.100.5, 192.168.4.1, 192.168.4.2 etc. from the router

I am not able to ping 192.168.4.1 from my PC

Any ideas are highly appreciated.

Please find the router configuration attached.

cadet alain · ‎08-24-2011

Hi,

verify your hosts fefault gateway is the ip address of your vlan interface.

Regards.

Alain.

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rrangelov · ‎08-24-2011

Hi,

It is verified. The default gateway for the hosts is the IP of the vlan.

BR

cadet alain · ‎08-24-2011

Hi,

Can you do a traceroute to 192.168.4.1 from pc.

Alain.

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rrangelov · ‎08-24-2011

I just tested. You can find the result below:

BR

cadet alain · ‎08-24-2011

Hi,

Ping again and do this

on the router:

int fa0/4

no ip route-cache

logging buffered 7

logging buffered 100000

access-list 180 permit icmp any any

debug ip icmp

debug ip pack detail 180

show log and post output

Regards.

Alain.

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rrangelov · ‎08-24-2011

KIWI(config)#int fa 4

KIWI(config-if)#no ip route-cache

KIWI(config-if)#exit

KIWI(config)#logging buffered 7

KIWI(config)#logging buffered 1000000

KIWI(config)#access-list 180 permit icmp any any

KIWI(config)#end

KIWI#debug ip icmp

ICMP packet debugging is on

KIWI#debug ip pack detail 180

IP packet debugging is on (detailed) for access list 180

KIWI#

When I try to ping 192.168.4.1 from my PC (192.168.100.5) nothing happens. There is no debug information.

BR

cadet alain · ‎08-24-2011

Hi,

It's normal the debug info is in the logging buffer, just do a show log and it will appear.

If it doesn't then do no ip route-chache under int vlan too and try again

Regards.

Alain.

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rrangelov · ‎08-24-2011

Here is the result from the show log command:

*Aug 24 09:53:25.215: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1, len 60, input

feature

*Aug 24 09:53:25.215: ICMP type=8, code=0, MCI Check(66), rtype 0, forus FAL

SE, sendself FALSE, mtu 0, fwdchk FALSE

*Aug 24 09:53:25.215: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1, len 60, input

feature

*Aug 24 09:53:25.215: ICMP type=8, code=0, TCP Adjust MSS(68), rtype 0, foru

s FALSE, sendself FALSE, mtu 0, fwdchk FALSE

*Aug 24 09:53:25.215: FIBipv4-packet-proc: route packet from Vlan1 src 192.168.1

00.5 dst 192.168.4.1

*Aug 24 09:53:25.215: FIBipv4-packet-proc: packet routing succeeded

*Aug 24 09:53:25.215: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1 (FastEthernet4)

, g=192.168.4.1, len 60, forward

*Aug 24 09:53:25.215: ICMP type=8, code=0

*Aug 24 09:53:25.215: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1 (FastEthernet4)

, len 60, sending full packet

*Aug 24 09:53:25.215: ICMP type=8, code=0

*Aug 24 09:53:30.375: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1, len 60, input

feature

*Aug 24 09:53:30.375: ICMP type=8, code=0, MCI Check(66), rtype 0, forus FAL

SE, sendself FALSE, mtu 0, fwdchk FALSE

*Aug 24 09:53:30.375: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1, len 60, input

feature

*Aug 24 09:53:30.375: ICMP type=8, code=0, TCP Adjust MSS(68), rtype 0, foru

s FALSE, sendself FALSE, mtu 0, fwdchk FALSE

*Aug 24 09:53:30.375: FIBipv4-packet-proc: route packet from Vlan1 src 192.168.1

00.5 dst 192.168.4.1

*Aug 24 09:53:30.375: FIBipv4-packet-proc: packet routing succeeded

*Aug 24 09:53:30.375: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1 (FastEthernet4)

, g=192.168.4.1, len 60, forward

*Aug 24 09:53:30.375: ICMP type=8, code=0

*Aug 24 09:53:30.375: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1 (FastEthernet4)

, len 60, sending full packet

*Aug 24 09:53:30.375: ICMP type=8, code=0

*Aug 24 09:53:35.875: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1, len 60, input

feature

*Aug 24 09:53:35.875: ICMP type=8, code=0, MCI Check(66), rtype 0, forus FAL

SE, sendself FALSE, mtu 0, fwdchk FALSE

*Aug 24 09:53:35.875: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1, len 60, input

feature

*Aug 24 09:53:35.875: ICMP type=8, code=0, TCP Adjust MSS(68), rtype 0, foru

s FALSE, sendself FALSE, mtu 0, fwdchk FALSE

*Aug 24 09:53:35.875: FIBipv4-packet-proc: route packet from Vlan1 src 192.168.1

00.5 dst 192.168.4.1

*Aug 24 09:53:35.875: FIBipv4-packet-proc: packet routing succeeded

*Aug 24 09:53:35.875: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1 (FastEthernet4)

, g=192.168.4.1, len 60, forward

*Aug 24 09:53:35.875: ICMP type=8, code=0

*Aug 24 09:53:35.875: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1 (FastEthernet4)

, len 60, sending full packet

*Aug 24 09:53:35.875: ICMP type=8, code=0

*Aug 24 09:53:41.375: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1, len 60, input

feature

*Aug 24 09:53:41.375: ICMP type=8, code=0, MCI Check(66), rtype 0, forus FAL

SE, sendself FALSE, mtu 0, fwdchk FALSE

*Aug 24 09:53:41.375: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1, len 60, input

feature

*Aug 24 09:53:41.375: ICMP type=8, code=0, TCP Adjust MSS(68), rtype 0, foru

s FALSE, sendself FALSE, mtu 0, fwdchk FALSE

*Aug 24 09:53:41.375: FIBipv4-packet-proc: route packet from Vlan1 src 192.168.1

00.5 dst 192.168.4.1

*Aug 24 09:53:41.375: FIBipv4-packet-proc: packet routing succeeded

*Aug 24 09:53:41.375: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1 (FastEthernet4)

, g=192.168.4.1, len 60, forward

*Aug 24 09:53:41.375: ICMP type=8, code=0

*Aug 24 09:53:41.375: IP: s=192.168.100.5 (Vlan1), d=192.168.4.1 (FastEthernet4)

, len 60, sending full packet

*Aug 24 09:53:41.375: ICMP type=8, code=0

*Aug 24 09:56:24.087: IP: s=192.168.4.27, d=224.0.0.2, pak 84AB2EB0 consumed in

input feature , packet consumed, MCI Check(66), rtype 0, forus FALSE, sendself

FALSE, mtu 0, fwdchk FALSE

cadet alain · ‎08-24-2011

Hi,

what is the design between your router and ISP?

Regards.

Alain.

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rrangelov · ‎08-24-2011

There is a very simple and stupid D-Link, I think. The idea is to change this D-Link with the router that I am trying to configure now. In order to test the new router I want to provide internet connectivity to its WAN port and create a test network on the other port. If I connect directly to the D-Link the TTL value is set to 64, so one more hop should not be a problem. There are no restrictions on the D-Link configured (it provides free Internet).

cadet alain · ‎08-24-2011

Hi,

So for now you are using a dsl dlink router/modem to connect to ISP and you want to replace by cisco router?

Did you connect router to dlink then dlink to internet with the router config you posted? If so I understand better why your ISP address was a private one because i suppose it corresponds to dlink inside addressing?

What is 192.168.4.1 ? the dlink address?

Could you clarify your topology please.

Regards.

Alain.

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rrangelov · ‎08-24-2011

You've got the idea terribly right 192.168.4.1 is the IP address of the D-Link. The D-Link is then connected to the ISP.

ISP-------D-Link------CISCO

cadet alain · ‎08-24-2011

Hi,

Th dlink hasn't got a route back to 192.168.100.5 so it can't work. You have to configure a static route for 192.168.100.0 on your dlink pointing to 192.168.4.100 which is address of your router directly connected link to dlink.

But then when you want to communicate on internet you'll have to tell the dlink to nat traffic from 192.168.100.0 or nat on the cisco router to 192.168.4.0.

Then if it is adsl have you got a wic adsl card in your router? if no then you'll have to leave the dlink as a modem by setting it in bridge mode and change your f0/4 config.

Regards.

Alain.

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