Re: DNS Over a Segment

Tech-Archive recommends: Repair Windows Errors & Optimize Windows Performance

From: Roland Hall (nobody_at_nowhere)
Date: 02/23/05 

Date: Tue, 22 Feb 2005 19:34:02 -0600

"Bill" wrote in message
news:5710A5B1-20D3-40C3-87BA-08984757FB8F@microsoft.com...
:
: "Roland Hall" wrote:
:
: > "Bill" wrote in message
: > news:F2BA7E02-937A-4BCD-8829-3401BABE26D7@microsoft.com...
: >
: > : I'm not sure what your asking about physical connections being
correct.
: > On
: > : segment-1, the ISP Router, Cisco-Router-1, and the DC/DNS all plug
into
: > the
: > : same switch. On segment-2, the router & all PC's connect to the same
: > switch.
: > :
: > : I do not have assigned addresses from my ISP. I have a static IP on
my
: > LAN
: > : side.
: > :
: > : On the ISP Router WAN side the settings are
: > : IP 209.143.5.191,
: > : Subnet 255.255.255.0,
: > : Default Gateway 209.143.5.1,
: > : DNS 209.143.0.10
: >
:
: > What is the LAN side of the ISP's router? The WAN side was not needed.
: > Why do you need two routers for two networks?
:
: I was told by the ISP I needed an additional router to attach to our
: network. Could we have connected the Internet Modem to our CISCO router
via
: the switch?

Well, if the ISP has a router at your location, then it is usually behind
the terminal devices, i.e. DSU/CSU

If you only have two private networks and one gateway to a public network,
you only really need one router as long as it has two LAN interfaces,
otherwise you do need one more, but not two more. You mentioned T-1,
referenced below so if you have this:

ISP Router -> LocalLoop -> ISP Router -> Switch1(LAN1) -> Router1 ->
LocalLoop -> LongHaul (T-1) -> LocalLoop -> Router2 -> Switch2(LAN2)

Then you do need two routers in lieu of the ISPs router on your end. If
LAN1/LAN2 were in the same physical location then it would become a design
issue to determine which router(s) were required.

: > It appears you have a router from the ISP at your location but it's
fuzzy
: > from there. Does the ISPs LAN connection connect to a switch? You have
a
: > 192.168.x.x network Serial-Serial between your two routers. You have
two
: > different Class B networks with two routers. So, the ISPs LAN side
address
: > is probably on the same subnet as Router1.
:
: Yes, the router from the ISP connects to a switch, the same switch as
: Router-1 and the DC/DNS server.
:
: The 192.168.x.x was there when I inherited the system. I'm not sure if it
: was used for anything or was just a default entry. The only connection
: between the routers is the Fastethernet0/0. Does that mean the
Serial-Serial
: setup is ignored?

>From the configs, Router1:Serial0/0 connects to Router2:Serial0/0. That is
the only way they connect.

: Yes, the ISPs LAN side address is the same subnet as Router1 and also the
: DC/DNS server.
:
:
: >
: > Is this what you have:
: >
: > ISP ROUTER] (LAN IP? 172.20.100.200 maybe?) -> [switch] ->
172.20.100.10/16
: > [Router1] 192.168.1.1/24 -> 192.168.1.2/24 [Router2] 172.21.100.10/16 ->
: > [switch]
:
: Yes, that looks pretty much right. We are using the Fastethernet0/0 so I
: don't think the 192.168.x.x (serial) applies here but I could be very
wrong!

It applies if you want Router2 to be connected and able to access the
Internet. Are these two LANs at the same location?

: > Router1's DFG is 192.168.1.2 WHY? Appears to be wrong. If
172.20.100.200
: > is the ISPs LAN IP address, then it should be that: 172.20.100.200
: Good question! I'll try changing this.
:
:
: > Router2's DFG is 192.168.1.1 which appears to be correct.
: OK
:
: >
: > Host: RM16 - remove 2nd gateway 172.20.100.10 You're not routing
through
: > Router1 to get to the net.
:
: OK, I think this was setup this was to allow the HAT's-Dell-2 to access a
PC
: on the second gateway in addition to accessing the internet.

What second gateway?

: > Host: Hats-Dell-2 - remove 2nd gateway 172.20.100.200 Your DFG is the
LAN
: > side of Router2, not the LAN side of the ISPs router.
:
: OK, I'll make the change!
:
:
: >
: > Also, you need a route back to the 172.21.0.0/16 network on the ISPs
router.
: > Otherwise it will think you are on the Internet and never route back to
you.
: > Your border router needs to know about all of your private networks.
The
: > private networks only need to know neighbors.
:
: OK, I'm not sure how to configure this in the ISP router but will work on
it!

If you have access to the ISP's router, all you need to do is add a route

Connect, logon, enable, type in enable password (comments in [])
conf t
[configuration terminal]
ip route 172.21.100.0 255.255.0.0 172.20.100.0
[ip route network mask interface]
wr mem or copy running-config startup-config
[write memory]

: > If LAN1 and LAN2 are connecting to the same switch, you have other
issues.
:
: Should be ok here, they connect to two separate switches on either side of
: the T-1.

This probably answers some questions above.

: > Don't forget to change your enable secret passwords on your routers
: > immediately. If you don't control your ISPs router at your location,
you
: > need to notify them right away to make config changes.
:
: Taken care of!

ok

: Many thanks!!!

You're welcome. How is connectivity now? 

-- 
Roland Hall
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How-to: Windows 2000 DNS: 
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http://support.microsoft.com/default.aspx?scid=kb;EN-US;291382

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