Why this default route doesn't work ?

  • Thread starter Thread starter Magoo
  • Start date Start date
M

Magoo

I have a Win2003 server named ISA with the following configuration under
TCP/IP Properties:

IP address=1.1.1.1
Subnet mask=255.0.0.0
Defaut gateway=1.1.1.254

That's it.

Now I need to make sure this server will reach mypublisheserver.com.
On the host file of ISA Server, I put
mypublished server 2.2.2.2.

Then I add a route:
Route add -p 2.2.2.0 MASK 255.0.0.0 1.1.1.254
I do a route print and I confirm the persistent, static route has been
added.

Then I ping mypublished server. It resolves to IP 2.2.2.2 accordingly, but
it returns:
"Destination host unreachable"

What's wrong ?
 
Well first of all, if the router/computer at 1.1.1.254 knows where to send
packets destined for 2.2.2.2, then there is no need for a static route.
Second, if the router/computer at 1.1.1.254 does not know where to send
packets destined for 2.2.2.2, then a static route pointing to that gateway
will not help. Finally, if you want to configure a static route to the
network on which 2.2.2.2 resides, it would be 2.0.0.0 NOT 2.2.2.0.

Doug Sherman
MCSE, MCSA, MCP+I, MVP
 
Pardon me, I sent you misinformation:
I have no default gateway set on the TCP/IP properties. That's why I
configured the default route.
correct, assume the subnet mask is correct (I edited the IP address before
posting this message and in the process I didn't reflect my correct mask).

Therefore all information is correct :
Assume I have the correct default route set with the right subnect mask:
route 2.2.2.0 MASK 255.0.0.0 1.1.1.254.
It still returns destination host unreachable.
How can this be ?
 
If the mask is correct, the command should be:

route add 2.0.0.0 MASK 255.0.0.0 1.1.1.254

If the network ID is correct but the mask is wrong, the command should be:

route add 2.2.2.0 MASK 255.255.255.0 1.1.1.254

Also, if you only need to reach one machine as opposed to an entire network,
you can use a static route with the host IP and a full mask:

route add 2.2.2.2 MASK 255.255.255.255 1.1.1.254

Doug Sherman
MCSE, MCSA, MCP+I, MVP
 
These will not work because he has no DG. He would have to add the route
with the next hop being on the local subnet. A detailed explanation was
posted at groupstudy.
 
Darn. Thanks !
We had this discussion here and folks told me that the default route should
do the 'job of a default' gateway, since the static route was saying which
gateway to go. Obviously that's not the case.
 
They will all work fine provided 1.1.1.254 knows how to find 2.2.2.2. A
default gateway is not necessary. The following connects to google just
fine:

Active Routes:
Network Destination Netmask Gateway Interface Metric
127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1
192.168.1.0 255.255.255.0 192.168.1.189 192.168.1.189 1
192.168.1.189 255.255.255.255 127.0.0.1 127.0.0.1 1
192.168.1.255 255.255.255.255 192.168.1.189 192.168.1.189 1
216.239.39.99 255.255.255.255 192.168.1.2 192.168.1.189 1
224.0.0.0 224.0.0.0 192.168.1.189 192.168.1.189 1
255.255.255.255 255.255.255.255 192.168.1.189 192.168.1.189 1

Doug Sherman
MCSE, MCSA, MCP+I, MVP
 
I spoke too soon. That's correct, the article below confirms that I wouldn't
need a default gateway (and I shouldn't) set it up on the second NIC:
http://support.microsoft.com/d­efault.aspx?scid=kb;en-us;­157025

In order to prove that 1.1.1.254 gateway knows the route to 2.2.2.2, I go to
another server which does have the default gateway configured=1.1.1.254.
From such server I ping 2.2.2.2 successfully.
That means 1.1.1.254 knows the route to 2.2.2.2


Any ideas ?
 
"on the second NIC" ?

First I've heard of the second NIC. Is it possible that you have 2 NICs on
the same subnet? This can cause all kinds of problems.

Doug Sherman
MCSE, MCSA, MCP+I, MVP
 
The computer is multihomed.

*Internet*-NIC
IP:1.78.253.1
Subnet:255.0.0.0
Default Gateway:1.78.253.254


Intranet-NIC:
IP:1.1.1.1
Subnet:255.0.0.0
(No default gateway)

Note that are although the subnet masks are the same on both NICs, the
networks are different. As far as i know that should not cause any problem.
Then I set the default gateway thru the route add command, but obviously
that is not working...
 
Both NICs are on the same subnet. Most likely this is the problem. Try
temporarily disabling the Local Area Connection for the Internet NIC and see
if you can connect to 2.2.2.2.

Doug Sherman
MCSE, MCSA, MCP+I, MVP
 
Doug I found the freaking problem: For whatever reason the rule I applied on
the ISA didn't take affect. Now I rebooted the computer and everything works
now. Thanks !
 
Go get 'em!

Doug Sherman
MCSE, MCSA, MCP+I, MVP

Magoo said:
Doug I found the freaking problem: For whatever reason the rule I applied on
the ISA didn't take affect. Now I rebooted the computer and everything works
now. Thanks !
Click to expand...
 
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