[isapros] Re: Came across this little gem...
- From: "Thor (Hammer of God)" <thor@xxxxxxxxxxxxxxx>
- To: <isapros@xxxxxxxxxxxxx>
- Date: Wed, 30 Jan 2008 07:01:35 -0800
Nasty bears are the worst. Particularly if they catch you out in the
woods sun-showering in a thong.
t
From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx]
On Behalf Of Jim Harrison
Sent: Wednesday, January 30, 2008 5:32 AM
To: isapros@xxxxxxxxxxxxx
Subject: [isapros] Re: Came across this little gem...
Yes, but the DNS server in a DoD connection is s special case.
Remember; this only happens If the local network defines a *local* DNS
server. If the local network defined an off-subnet DNS server, then the
DoD DNS server would be tried frist.
BTDT; was a nasty bear to sort out.
Jim
From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx]
On Behalf Of Thor (Hammer of God)
Sent: Tuesday, January 29, 2008 9:50 PM
To: isapros@xxxxxxxxxxxxx
Subject: [isapros] Re: Came across this little gem...
In XP, the VPN client DNS is prioritized, so it's not an issue. And in
Vista, you can tell it to "use the default gateway on the remote
network" to query the DNS server specified in the VPN connection.
t
From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx]
On Behalf Of Jim Harrison
Sent: Tuesday, January 29, 2008 9:11 PM
To: ISA Mailing List; ISAPros Mailing List
Subject: [isapros] Re: Came across this little gem...
Yep - these are the same geniuses that choose to respond for domains
they don't hold.
Case in point:
C:\>nslookup -d anyhost.corp.microsoft.com. 208.67.222.222
------------
Got answer:
HEADER:
opcode = QUERY, id = 1, rcode = NOERROR
header flags: response, want recursion, recursion avail.
questions = 1, answers = 1, authority records = 0, additional
= 0
QUESTIONS:
222.222.67.208.in-addr.arpa, type = PTR, class = IN
ANSWERS:
-> 222.222.67.208.in-addr.arpa
name = resolver1.opendns.com
ttl = 82245 (22 hours 50 mins 45 secs)
------------
Server: resolver1.opendns.com
Address: 208.67.222.222
------------
Got answer:
HEADER:
opcode = QUERY, id = 2, rcode = NOERROR
header flags: response, want recursion, recursion avail.
questions = 1, answers = 1, authority records = 0, additional
= 0
QUESTIONS:
anyhost.corp.microsoft.com, type = A, class = IN
ANSWERS:
-> anyhost.corp.microsoft.com
internet address = 208.67.216.130
ttl = 0 (0 secs)
------------
Non-authoritative answer:
Name: anyhost.corp.microsoft.com
Address: 208.67.216.130
What's the problem with this you may ask (go ahead - I triple-dog-dare
ya)?
Take the case of the home (or small business) user chooses to use their
DNS in their NAT device.
In many cases, this NAT device also acts as the local network "DNS
proxy" in that the DHCP service it provides assigns its NAT IP (say;
192.168.0.1) as the DNS server for the internal hosts.
Now let's this user has the ability to create a VPN connection to
Microsoft. When this connection is created, the VPN client has two DNS
servers to query; the local NAT DNS provided by the DHCP assignment and
the DNS server supplied via the VPN connection.
When Windows tries to resolve <host>.corp.microsoft.com, the closest DNS
server is the one defined in the non-DoD network, or 192.168.0.1.
This DNS server, being nothing more than a NAT reference to the OpenDNS
"services" replies to this request with an IUP address that is *not*
found within MS internal address space. Thus, the user can never make a
name-based connection across the VPN tunnel.
Apparently, they query the authoritative DNS services and if they come
up empty, the respond with an address anyway.
We tried working with them to stop doing this, but to no avail.
While my (real-life) example is Microsoft-specific, it would work if the
domain was ISAtools.org.
Consider using this "service" carefully; it'll bite you in the butt when
you least expect it.
Jim
From: isalist-bounce@xxxxxxxxxxxxx [mailto:isalist-bounce@xxxxxxxxxxxxx]
On Behalf Of Steve Moffat
Sent: Tuesday, January 29, 2008 3:50 PM
To: ISA Mailing List; ISAPros Mailing List
Subject: [isalist] Came across this little gem...
Looks like this could very well compliment your ISA installs guys...
http://www.opendns.com
Thanks
Steve
Steve Moffat
Operations Director
Optimum IT Solutions
Desk: 441 292 8849
Mobile: 441 292 8849
MSN IM: steve@xxxxxxxxxx
Web: http://optimum.bm <http://optimum.bm/>
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