01-27-2015 02:39 AM - edited 03-05-2019 12:39 AM
please help!!!
Im using a cisco 1841 router with one vlan1 on it to access internet and it work..recently i wanted to create a second vlan 2 i have done all the configuration nat,access-list i can ping vlan2 from the pcs but this vlan2 cant access internet ..what config should i do?thank you
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01-27-2015 04:33 AM
You duplicated to much of the config as both VLANs will use the same NAT and dialer-interface to communicate to the internet.
First remove the unneeded config:
no ip nat inside source list 2 interface dialer2 overload no dialer-list 2 protocol ip permit no access-list 2 permit 192.168.x.x 0.0.0.255
The only thing you need in addition to your new vlan is the config that the new VLAN should also do NAT:
access-list 1 permit 192.168.x.x 0.0.0.255
01-27-2015 05:10 AM
no, the new line will be added to the list and both networks will get NATed.
01-27-2015 03:08 AM
Are the PCs using the vlan2-ip as the default-gateway?
If yes, there is probably something wrong with your ACL or NAT-config. Please post your config (with removed passwords).
01-27-2015 04:12 AM
yeah vlan2 will be use as gateway..here is the config
interface fastethernet0
switchport access vlan2
no ip address
!
interface fastethernet1
no ip address
!
interface fastethernet2
no ip address
!
interface fastethernet3
no ip address
!
interface fastethernet4
description wan interface to
no ip address
load-interval 30
duplex full
speed 100
pppoe enable group global
pppoe-client dial-pool-number 1
!
interface vlan1
description to custumer lan
ip address 10.1.x.x 255.255.0.0
ip nat inside
ip virtual-reassembly in
!
interface vlan2
ip address 192.168.x.x 255.255.255.0
ip nat inside
ip virtual-reassembly in
!
interface dialer 1
description pppoe session customer 6/2 mb
ip ddns update hostname xxxxxxxxxxxx
ip ddns update noip
ip address negociated
ip mtu 1452
ip nat outside
ip virtual-reassembly in
encapsulation ppp
ip top adjust-mss 1452
load-interval 30
dialer pool 1
dialer-group 1
ppp chap hostname xxxxxxxx
ppp chap password xxxxxxxx
!
ip forward-protocol nd
no ip http server
no ip fttp secure-server
!
!
ip nat inside source list 1 interface dialer1 overload
ip nat inside source list 2 interface dialer2 overload
ip route 0.0.0.0 0.0.0.0 dialer1
!
dialer-list 1 protocol ip permit
dialer-list 2 protocol ip permit
!
snmp-server community
access-list 1 permit 10.1.x.x 0.0.255.255
access-list 2 permit 192.168.x.x 0.0.0.255
!
control-plane
!
!
mgcp behavior rsip-range tgcp-only
mgcp behavior comedia-role non
mgcpbehavior comedia-check-media-src disable
mgcp behavior comedia-sdp-fore disable
!
mgcp profile default
!
!
01-27-2015 04:33 AM
You duplicated to much of the config as both VLANs will use the same NAT and dialer-interface to communicate to the internet.
First remove the unneeded config:
no ip nat inside source list 2 interface dialer2 overload no dialer-list 2 protocol ip permit no access-list 2 permit 192.168.x.x 0.0.0.255
The only thing you need in addition to your new vlan is the config that the new VLAN should also do NAT:
access-list 1 permit 192.168.x.x 0.0.0.255
01-27-2015 04:39 AM
thank you..but will the command 'access-list 1 permit 192.168.x.x 0.0.0.255' will make vlan1 stop working?
01-27-2015 05:10 AM
no, the new line will be added to the list and both networks will get NATed.
01-27-2015 08:16 AM
thanks a lot karsten it works :) cheers
01-27-2015 04:35 AM
One more thing. For PPPoE, the MTU is typically 1492 unless told from the ISP to use something different:
interface dialer 1 ip mtu 1492
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