DNS Forwarding Not Work

[mmsameed]

I have simpe network like follow,
DSL Modem------> ISA Server ----> Switch--->PDC, BDC, Exchange,.....

All Servers Windows 2003 SP2,

In Our DNS Server (PDC) I have put Our ISP DNS Addresses as
Forwarders. But it is Not working. I mean i can not Browse internet
even i can not ping, nslookup any Internet site or IP.
I thought it was becaouse of ISA Firewall. then now i have Unstall the
ISA Server Services for time being to test the Forwarding. even not
working.

ISA Serve MAchine IP address

External Interafce : IP : Static, Default Gateway: DSL Modem IP, DNS :
Empty
Internal Interface: IP: Local Static IP : Default Gateway: Empty, DNS:
Local DNS Servers.

At the same time PDC's interface: IP: Static : Default Gateway: ISA
Server IP, DNS: Local DNS


When i try NSLookup from PDC to ISP DNS Server :

++++++++++++++++++++++++++++++++
C:\>nslookup ISP DNS Server or IP
Server: PDCname.Doamin.com
Address: 192.168.*.*

DNS request timed out.
timeout was 2 seconds.
*** Request to PDCname.Doamin.com timed-out
+++++++++++++++++++++++++++++++++++

Please be noted now there is no Firwall Server (ISA) not installed.

But Local NSLOOKUP is working fine.

Please Any one Help Me.

 

[Meinolf Weber]

Hello (e-mail address removed),

Did yuou configure the ISP's DNS on the NIC of the DNS server or in the DNS
management console under the forwarders tab? Please post an unedited ipconfig
/all from DNS server.

And just a remark, since windows 2000 there is no longer a PDC?BDC concept.
All DOmain controllers are the same, the differences are the 5 FSMO roles
used in the domain controllers.

Best regards

Meinolf Weber
Disclaimer: This posting is provided "AS IS" with no warranties, and confers
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[Herb Martin]

I have simpe network like follow,
DSL Modem------> ISA Server ----> Switch--->PDC, BDC, Exchange,.....

All Servers Windows 2003 SP2,

In Our DNS Server (PDC) I have put Our ISP DNS Addresses as
Forwarders. But it is Not working. I mean i can not Browse internet
even i can not ping, nslookup any Internet site or IP.
I thought it was becaouse of ISA Firewall. then now i have Unstall the
ISA Server Services for time being to test the Forwarding. even not
working.

In Win2000+ there are no PDC/BDCs, only DCs (although one of the
DC will be the "PDC-Emulator" in general, for most purposes all DCs
are equal.)

What happens when you use NSLookup from the INSIDE (say on the
internal DC-DNS server to check the ISP DNS?

nslookup www.google.com IP.Address.ISP.DNS

If this works you don't have a FIREWALL/ISA issue. If this does NOT
work then you don't (primarily) have a problem with the Internal DNS
servers. (Although the internal DNS servers could be misconfigured IN
ADDITION.)

But also try some other (known working) external DNS server to prove
that it isn't simply a problem with the ISP dns or your having the WRONG
ISP DNS address:

nslookup www.google.com 4.2.2.2

ISA Serve MAchine IP address

External Interafce : IP : Static, Default Gateway: DSL Modem IP, DNS :
Empty
Internal Interface: IP: Local Static IP : Default Gateway: Empty, DNS:
Local DNS Servers.

Generally correct. Since ISA is usually a "Member" of your internal Domain
it must use ONLY the internal DNS even though this requires you to
(sometimes) override the ISP-DHCP assigned DNS setting on the external
NIC.

At the same time PDC's interface: IP: Static : Default Gateway: ISA
Server IP, DNS: Local DNS


When i try NSLookup from PDC to ISP DNS Server :

++++++++++++++++++++++++++++++++
C:\>nslookup ISP DNS Server or IP
Server: PDCname.Doamin.com
Address: 192.168.*.*

DNS request timed out.
timeout was 2 seconds.
*** Request to PDCname.Doamin.com timed-out

Try
nslookup www.google.com 4.2.2.2

If this also fails this points strongly to the (filter on) the ISA server.