[isalist] Re: wpad.dat DNS entry

  • From: "Ball, Dan" <DBall@xxxxxxxxxxx>
  • To: <isalist@xxxxxxxxxxxxx>
  • Date: Fri, 1 Sep 2006 07:20:07 -0400

Okay, my bad, someday I'll get those terms right...  What you say makes
sense, it's definitely an option...

 

I'm just hoping our WAN fiber goes into place soon, then I won't have to
worry about multiple internal sub-nets anymore...

 

________________________________

From: isalist-bounce@xxxxxxxxxxxxx [mailto:isalist-bounce@xxxxxxxxxxxxx]
On Behalf Of Roy Tsao
Sent: Thursday, August 31, 2006 2:25 PM
To: isalist@xxxxxxxxxxxxx
Subject: [isalist] Re: wpad.dat DNS entry

 

Hi Dan,

 

I said "Except SNAT".

 

Moreover, unless special client required as SNAT like published server,
FWC plus WPC shall be deployed to most of

clients under ISA Firewall environment, we can maximize the benefit
provided by ISA, right?

So even if there is gateway at client side, most of them shall go
through FWC or WPC connection.

Again, I try to say the positive point of DNS round robin feature,
that's it.

 

HTH,

 

Roy 

        ----- Original Message ----- 

        From: Thomas W Shinder <mailto:tshinder@xxxxxxxxxxx>  

        To: isalist@xxxxxxxxxxxxx 

        Sent: Friday, September 01, 2006 1:37 AM

        Subject: [isalist] Re: wpad.dat DNS entry

         

        I've done it in many deployments, and IIRC, that's how they do
it at MS.

         

        Thomas W Shinder, M.D.
        Site: www.isaserver.org
        Blog: http://blogs.isaserver.org/shinder/
        Book: http://tinyurl.com/3xqb7
        MVP -- ISA Firewalls

         

                 

                
________________________________


                From: isalist-bounce@xxxxxxxxxxxxx
[mailto:isalist-bounce@xxxxxxxxxxxxx] On Behalf Of Ball, Dan
                Sent: Thursday, August 31, 2006 12:26 PM
                To: isalist@xxxxxxxxxxxxx
                Subject: [isalist] Re: wpad.dat DNS entry

                We had briefly touched upon this topic about a year or
so ago, but I wasn't aware that it was an actual common practice...

                 

                
________________________________


                From: isalist-bounce@xxxxxxxxxxxxx
[mailto:isalist-bounce@xxxxxxxxxxxxx] On Behalf Of Thomas W Shinder
                Sent: Thursday, August 31, 2006 12:18 PM
                To: isalist@xxxxxxxxxxxxx
                Subject: [isalist] Re: wpad.dat DNS entry

                 

                Hi Dan,

                 

                In most secure environments you don't give the clients a
default gateway and use the Firewall and Web proxy client configurations
to enfroce security. So, this might work fine using RR DNS.

                 

                Thomas W Shinder, M.D.
                Site: www.isaserver.org <http://www.isaserver.org/> 
                Blog: http://blogs.isaserver.org/shinder/
                Book: http://tinyurl.com/3xqb7
                MVP -- ISA Firewalls

                 

                         

                        
________________________________


                        From: isalist-bounce@xxxxxxxxxxxxx
[mailto:isalist-bounce@xxxxxxxxxxxxx] On Behalf Of Ball, Dan
                        Sent: Thursday, August 31, 2006 11:02 AM
                        To: isalist@xxxxxxxxxxxxx
                        Subject: [isalist] Re: wpad.dat DNS entry

                        I'd have to say no...

                        -          External sites are resolved by DNS
server.

                        -          Resolved sites are referenced then by
IP address.

                        -          Since an external site is resolved to
an IP that is not a "local" address, it resorts to using the default
gateway to connect.

                        -          Default gateways are entered by IP,
not hostname, nullifying the round-robin DNS abilities.

                         

                        The exception to this might be if you use the
FWC, then you might be able to redirect all connections via DNS entries.
You might be able to share the proxy address too, but that default
gateway is a kicker...

                         

                        
________________________________


                        From: isalist-bounce@xxxxxxxxxxxxx
[mailto:isalist-bounce@xxxxxxxxxxxxx] On Behalf Of Roy Tsao
                        Sent: Thursday, August 31, 2006 10:00 AM
                        To: isalist@xxxxxxxxxxxxx
                        Subject: [isalist] Re: wpad.dat DNS entry

                         

                        Hm...

                         

                        You have two ISA SE, let say its internal
interface IP address is 192.168.0.1/24 and 192.168.0.2/24.

                        You creat two a record in DNS, isa.dan.local ->
192.168.0.1   and  isa.dan.local -> 192.168.0.2

                        Then by DNS round robin, your internal client
(except SNAT) would enjoy the connection to either

                        of the ISA SE server for ounbound connection,
make sense? 

                                ----- Original Message ----- 

                                From: Ball, Dan
<mailto:DBall@xxxxxxxxxxx>  

                                To: isalist@xxxxxxxxxxxxx 

                                Sent: Thursday, August 31, 2006 9:01 PM

                                Subject: [isalist] Re: wpad.dat DNS
entry

                                 

                                I think that would only work on inbound
connections.  You can't define round-robin DNS entries for someone
else's server!

                                 

                                
________________________________


                                From: isalist-bounce@xxxxxxxxxxxxx
[mailto:isalist-bounce@xxxxxxxxxxxxx] On Behalf Of Roy Tsao
                                Sent: Thursday, August 31, 2006 8:42 AM
                                To: isalist@xxxxxxxxxxxxx
                                Subject: [isalist] Re: wpad.dat DNS
entry

                                 

                                Surely about outbound connection!

                                ----- Original Message ----- 

                                From: Ball, Dan
<mailto:DBall@xxxxxxxxxxx>  

                                To: isalist@xxxxxxxxxxxxx 

                                Sent: Thursday, August 31, 2006 8:34 PM

                                Subject: [isalist] Re: wpad.dat DNS
entry

                                 

                                You referring to incoming or outgoing
connections? 

                                 

                                
________________________________


                                From: isalist-bounce@xxxxxxxxxxxxx
[mailto:isalist-bounce@xxxxxxxxxxxxx] On Behalf Of Roy Tsao
                                Sent: Thursday, August 31, 2006 8:28 AM
                                To: isalist@xxxxxxxxxxxxx
                                Subject: [isalist] Re: wpad.dat DNS
entry

                                 

                                Dan,

                                 

                                Suppose you have two external line
provided by different ISP, normally two ISA EE is needed 

                                but by using DNS round robin, you can
deploy two ISA SE for load balancing..., that's my

                                point.

                                 

                                HTH,

                                 

                                Roy 

                                ----- Original Message ----- 

                                From: Ball, Dan
<mailto:DBall@xxxxxxxxxxx>  

                                To: isalist@xxxxxxxxxxxxx 

                                Sent: Thursday, August 31, 2006 8:19 PM

                                Subject: [isalist] Re: wpad.dat DNS
entry

                                 

                                No, you would still have that "one
default gateway" problem...  Besides, that feature is only for DNS
entries that "you" control, not external.

                                 

                                
________________________________


                                From: isalist-bounce@xxxxxxxxxxxxx
[mailto:isalist-bounce@xxxxxxxxxxxxx] On Behalf Of Roy Tsao
                                Sent: Thursday, August 31, 2006 4:36 AM
                                To: isalist@xxxxxxxxxxxxx
                                Subject: [isalist] Re: wpad.dat DNS
entry

                                 

                                Dan,

                                 

                                Your problem is due to DNS round robin
feature, and it shall be solved by Stefaan's great 

                                guidance. 

                                On the other hand, don't you think we
can utilize such round rodin as a good feature to

                                implement NLB to balance connection to
multi external interface by using ISA STD version

                                only?

                                 

                                HTH,

                                 

                                Roy Tsao

                                ----- Original Message ----- 

                                From: Stefaan Pouseele
<mailto:stefaan.pouseele@xxxxxxxxx>  

                                To: isalist@xxxxxxxxxxxxx 

                                Sent: Thursday, August 31, 2006 4:08 PM

                                Subject: [isalist] Re: wpad.dat DNS
entry

                                 

                                you might check out
http://support.microsoft.com/?kbid=842197. 

                                 

                                HTH, 

                                Stefaan

                                 

                                
________________________________


                                From: isalist-bounce@xxxxxxxxxxxxx
[mailto:isalist-bounce@xxxxxxxxxxxxx] On Behalf Of Ball, Dan
                                Sent: donderdag 31 augustus 2006 3:28
                                To: isalist@xxxxxxxxxxxxx
                                Subject: [isalist] Re: wpad.dat DNS
entry

                                Good article, it sounds very similar to
my scenario.  I already had the "enable netmask ordering" option
enabled, so that is not the problem.  Do you think it might be because
each of the 10.6.x.x subnets have a mask of 255.255.255.0?  

                                 

                                 

                                 

                                
________________________________


                                From: isalist-bounce@xxxxxxxxxxxxx
[mailto:isalist-bounce@xxxxxxxxxxxxx] On Behalf Of Stefaan Pouseele
                                Sent: Wednesday, August 30, 2006 3:57 PM
                                To: isalist@xxxxxxxxxxxxx
                                Subject: [isalist] Re: wpad.dat DNS
entry

                                 

                                Hi Dan, 

                                 

                                check out my blog
http://blogs.isaserver.org/pouseele/2006/06/30/multi-networking-wpad-sup
port-in-isa-2004/. 

                                 

                                HTH, 

                                Stefaan

                                 

                                
________________________________


                                From: isalist-bounce@xxxxxxxxxxxxx
[mailto:isalist-bounce@xxxxxxxxxxxxx] On Behalf Of Ball, Dan
                                Sent: woensdag 30 augustus 2006 21:47
                                To: isalist@xxxxxxxxxxxxx
                                Subject: [isalist] wpad.dat DNS entry

                                I'm having a serious problem here with
the wpad name resolution.  I moved it from being sent out via DHCP to
DNS per Jim's recommendation, which seems to have speeded up some
things, but is now unreliable and causing problems.

                                 

                                The problem appears to be the multiple
internal subnets...  Here is a diagram of how it is laid out:

                                 

                                Internet

                                    |

                                ISA Server --- Internal Network 1
(10.20.1.1)

                                    |

                                Internal Network 2 (10.6.254.90)----
10.6.8.x Subnet

        
|-- 10.6.9.x Subnet

        
|-- 10.6.10.x Subnet

        
|-- 10.6.12.x Subnet

        
|-- 10.6.14.x Subnet

        
|-- 10.6.15.x Subnet

                                    

                                I entered two Host (A) records for wpad,
one for 10.20.1.1, and another for 10.6.254.90.  

                                 

                                Frequently I run across computers on the
10.6.x.x subnet where the FWC cannot automatically detect the ISA
server, so I ping wpad and it resolves to the 10.20.1.1 address instead
of the 10.6.254.90 address that it is supposed to get.  I try repairs
and such, it keeps resolving to the wrong one.  When I reboot the
computer, it resolves to the correct IP and works properly.  I reboot
the computer several times, and it gets the correct address.  But, I'll
hear of another computer having problems, and I'll check and it is the
same problem.  This is not going to be pretty over the next few days as
teacher come back to work after summer vacation.

                                 

                                What is the best way to resolve this?
Change it back to DHCP, customize host files, etc?  

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