Redirect DNS traffic

[Rodrigo Fialho]

Hello.

I'm facing a trouble.

I'm trying to redirect the DNS traffic for a specific server, DNS lookup-based content filter server. I'm using bellow configuration to redirect traffic:

Content filter: 172.16.0.130

access-list 100 permit udp 192.168.0.0 0.0.0.255 any eq domain

!

route-map dns permit 10
match ip address 100
set ip next-hop 172.16.0.130

!

interface GigabitEthernet0/0
ip address 192.168.255.2 255.255.255.0
no ip redirects
ip nat outside
ip virtual-reassembly in
ip verify unicast source reachable-via rx allow-default
duplex auto
speed auto
media-type rj45

!

interface GigabitEthernet0/1.10
encapsulation dot1Q 10
ip address 172.16.0.1 255.255.255.128
ip nat inside
no ip virtual-reassembly in
!
interface GigabitEthernet0/1.15
encapsulation dot1Q 15
ip address 172.16.0.129 255.255.255.128
ip nat inside
no ip virtual-reassembly in
!
interface GigabitEthernet0/1.20
encapsulation dot1Q 20
ip address 192.168.0.1 255.255.255.0
ip nat inside
no ip virtual-reassembly in
ip policy route-map dns

Workstations at 192.168.0.0/24 can't surf the internet.

[Jaderson Pessoa]

Hello,

What dns address your workstation are receiving?

[Rodrigo Fialho]

Hello,

I have some unmanned computers on my LAN and these computers can use any dns address, so I need to forcing these computers to query a specific dns server.

[balaji.bandi]

For the question is for this range IP address: 192.168.0.0/24 what is the DNS Server?

!
ip access-list extended BB_DNS_REDIRECT
permit tcp 192.168.0.0 0.0.0.255 eq domain any
permit udp 192.168.0.0 0.0.0.255 eq domain any
!
!
route-map BB_RMAPDNS  permit 10
match ip address BB_DNS_REDIRECT
set ip next-hop 172.16.0.130
!

Apply to interface.

[Rodrigo Fialho]

Hello,

For the question is for this range IP address: 192.168.0.0/24 what is the DNS Server?

This is my LAN address.

I made a configuration bellow but it does not work.

[balaji.bandi]

is your PC connfigured using DHCP or Static IP, what is the DNS Address you entering there ?

[Rodrigo Fialho]

Hello,

I am using both dhcp or static IP, workstations can use any DNS address.

[balaji.bandi]

Just to precise to work on more granular, give example of what DNS you have used at client end which was not worked.

is the rule matching and your ACL? check the logs make sure it is hitting the interface on the first level. we need more information and logs - since we do not any visibility to help here. (Technically it should work, hence we need to investigate what is the issue ) /

[Rodrigo Fialho]

Hello.

See the attached, please.

You'll understand better my trouble at least I think so.

Thanks.