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ROUTER HELL (Why is my Linksys doing it but not the Cisco) 3

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sweeney1975

Technical User
Joined
Mar 4, 2005
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5
Location
GB
I share my internet connection using a Linksys BEFSR41 I want to do this using a cisco 2611 and cisco 1924 switch. This config gets a ip from my isp and the computers on the lan side get a ip from the router dhcp service. The computers can access the internet for a couple of mins then connection stops. If i look at the output for debug IP NAT it is still going crazy even though the computers and router can still not see the outside web.
I can still ping the router and the adress assigned to eth0/0 but anything past this times out!! My config is below, Am i missing something or do you think this is to do with my cable modem (motorola SB4100) or my ISP (Telewest Blueyonder). Some one please help as I want to get rid of the Linksys and use the cisco 2611......

sh run
Building configuration...

Current configuration : 1298 bytes
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname EAGLE1
!
aaa new-model
aaa authentication login default local
aaa authorization exec default local
enable secret 5 $1$BShd$.ItWs5Z1vwvY3iVQKVEeV/
enable password 7 030054040B0A25
!
username EAGLE2 password 7 03174F04080A33435D0C0A
username Sweeney password 7 111A0D0A19171903172F38
ip subnet-zero
!
!
ip host EAGLE3 192.168.3.2
ip host EAGLE2 192.168.2.2
ip dhcp excluded-address 192.168.1.1 192.168.1.9
ip dhcp excluded-address 192.168.1.50 192.168.1.255
!
ip dhcp pool EYESTRAIN
network 192.168.1.0 255.255.255.0
default-router 192.168.1.1
dns-server 62.31.144.39 195.188.53.175
!
!
!
!
interface Ethernet0/0
ip address dhcp client-id Ethernet0/0
ip nat outside
full-duplex
!
interface Serial0/0
ip address 192.168.2.1 255.255.255.0
encapsulation ppp
shutdown
ppp authentication chap
!
interface Ethernet0/1
ip address 192.168.1.1 255.255.255.0
ip nat inside
full-duplex
no cdp enable
!
ip nat inside source list 1 interface Ethernet0/0 overload
ip classless
no ip http server
!
access-list 1 permit 192.168.1.0 0.0.0.255
!
line con 0
password 7 071C3543400C0B0A041718
logging synchronous
line aux 0
line vty 0 4
password 7 105D1D160B1200041F0139
!
end
 
Where is your route statement?

ip route 0.0.0.0 0.0.0.0 ethernet 0/0

 
Yep...need default route.
May also want to use extended access list.

ip nat inside source list 102 interface Ethernet0/0 overload

access-list 102 permit ip 192.168.1.0 0.0.0.255 any

Leave access-list 1 and apply to line vty 0 4 for security.

line vty 0 4
login
access-class 1 in

Also:
no ip http server
no ip directed-broadcast

Hope this is useful......
 
Thanks going to try this but i am sure that i have tried it before with the default route and still did not work properly. Will try the extended access list idea though. Thanks for the quick response guys any other ideas from anyone I am all ears.....
 
Also your connection to your cable modem looks like it is set to full duplex , i haven't seen a home user cable modem yet that is 10/full , I would change this to half duplex because the way it is now you have a speed/duplex mismatch and this will cause all kinds of errors and response time problems . This may be causing your problem .
 
lads I think that vipergg hit the nail on the head after much stressing my connection seems to be working a treat now.... Thanks all for the advice. Can any one tell me how i would have debugged this problem to find out that the duplex settings were not matching and causing the errors, is there any obvious show or debug commands... Thanks again a happy cisco 2611 router user..... Goodbye Linksys, looks like I am going to have to think about access-lists now to get her locked down...
 
If you did a show interface on the cable modem connection it should have shown all kinds of errors and even collisions because the other was set as half duplex . Home cable modems that I have seen are 10/half duplex . If you are running connections between say cisco devices each end must match , if one end is auto then code the other end as auto , if you hardcode one side to say 100/full then the other end "must" be set as 100/full .
 
PS I noticed that you have your connection to your 1924 is set as full also , a port on a 1924 is default as half duplex so make sure you hardcode the 1924 port connection to full also other that will slow you down also .
 
Nice one for the heads up, i got that one done allready. Just did not think it through on the cable modem end. Thanks again
 
You don't need to specify a default route

using the dhcp client, should provide that for you..

 
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