Cisco 857 Router - workstations not connecting to internet.

[Ian Mullan]

Hi all,

I'm a completely new to Cisco equipment. I bought a 857 router to try and teach myself the basics.

So far I can get the router to connect to by BT ADSL broadband. The CD and PPP lights are on and I can ping websites from the router. However I cant get any Win7 workstations to connect to the Internet.

Any help is appreciated.

Regards

Ian

========================================================

version 12.4
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$wv5V$MS4gKwHsCKetNsg4UqnPc0
!
no aaa new-model
!
!
dot11 syslog
no ip dhcp use vrf connected
ip dhcp excluded-address 192.168.0.1 192.168.0.4
!
ip dhcp pool sdm-pool1
   network 192.168.1.0 255.255.255.0
   domain-name dns.domain.name
   dns-server 213.120.234.58 213.120.234.26
   default-router 192.168.1.1
!
!
ip cef
ip name-server 213.120.234.58
ip name-server 213.120.234.26
!
!
!
!
!
archive
 log config
  hidekeys
!
!
!
!
!
interface ATM0
 no ip address
 no atm ilmi-keepalive
 dsl operating-mode auto
!
interface ATM0.1 point-to-point
 pvc 0/38
  encapsulation aal5mux ppp dialer
  dialer pool-member 1
 !
!
interface FastEthernet0
!
interface FastEthernet1
!
interface FastEthernet2
!
interface FastEthernet3
!
interface Vlan1
 ip address 192.168.1.1 255.255.255.0
 ip nat inside
 ip virtual-reassembly
!
interface Dialer0
 ip address negotiated
 ip nat outside
 ip virtual-reassembly
 encapsulation ppp
 dialer pool 1
 dialer-group 1
 no cdp enable
 ppp authentication chap callin
 ppp chap hostname bthomehub@btbroadband.com
 ppp chap password 0 BT
 hold-queue 224 in
!
ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 Dialer0
!
no ip http server
no ip http secure-server
!
access-list 1 permit 192.168.1.0 0.0.0.255
dialer-list 1 protocol ip permit
!
control-plane
!
!
line con 0
 no modem enable
line aux 0
line vty 0 4
!
scheduler max-task-time 5000
end

========================================================

Router#show ip interface brief
Interface                        IP-Address        OK?   Method  Status           Protocol
FastEthernet0              unassigned        YES unset      up                    up
FastEthernet1              unassigned        YES unset      down               down
FastEthernet2              unassigned        YES unset      up                    down
FastEthernet3              unassigned        YES unset      up                    down
ATM0                            unassigned        YES NVRAM up                    up
ATM0.1                         unassigned        YES unset      up                    up
Vlan1                            192.168.1.1        YES NVRAM up                    up
NVI0                              unassigned         YES unset  administratively down down
Dialer0                          86.184.50.127   YES IPCP     up                    up
Virtual-Access1           unassigned         YES unset     up                    up
Virtual-Access2           unassigned         YES unset     up                    up

========================================================

[Seb Rupik · Accepted solution]

Hi Ian,

Try adding the following:

!

access-list 101 permit ip 192.168.1.0 0.0.0.255 any

!

ip nat inside source list 101 interface Dialer0 overload

!

cheers,

Seb.

[Ian Mullan]

Thanks a million Seb, that worked. You're my new best friend !!

Can you briefly explain why I need these two lines?

[Seb Rupik]

No problem.

!

access-list 101 permit ip 192.168.1.0 0.0.0.255 any

!

Configures an ACL '101' which permits all IP traffic with a source address of 192.168.1.0 /24 ; your 'inside' network. If at a later date you had more internal subnets, you would need to add them to this access list, or edit the subnet mask of this one entry to increase its scope.

!

ip nat inside source list 101 interface Dialer0 overload

!

You have already defined 'interface Vlan1' as the 'inside' interface. This information is required for NAT.

The line essential says: NAT all traffic arriving on the 'inside' interface which is permited by the ACL 101, then SNAT it using the Dialer0 interface. The overload paramter allows multiple inside sources to be NAT'd to this one interface.

If you want to know more, take a look here:

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_nat/configuration/15-mt/nat-15-mt-book/iadnat-addr-consv.html

cheers,

Seb.

[Ian Mullan]

Ok cheers for that and thanks for al your help Seb.