[isalist] Re: wpad.dat DNS entry

  • From: "Ball, Dan" <DBall@xxxxxxxxxxx>
  • To: <isalist@xxxxxxxxxxxxx>
  • Date: Thu, 31 Aug 2006 12:01:33 -0400

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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