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Stupid newbie question

 
 
thetownrecluse
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Posts: n/a
 
      01-07-2005
This is an education situation. I believe I can do this, but not sure

I have multiple machines on a 192.168.100.x switch. All addresses are
static.

For learning purposes I wanted to insert a router between the switch and one
of the computers.

I have subnetted the address space in half with mask 255.255.255.128 on the
machines. I have that up and running.

The router has one interface at 192.168.100. 7 255.255.255.128 and the other
at 192.168.100.130 255.255.255.128.

I can ping all network addresses from the router. From 192.168.100.132
address I can ping the 192.168.100.130.

interface Ethernet0
ip address 192.168.100.130 255.255.255.12
no ip route-cache
no ip mroute-cache
!
interface Ethernet1
ip address 192.168.100.7 255.255.255.128
no ip route-cache
no ip mroute-cache
!
..
..
..
..
ip classless
ip route 192.168.100.0 255.255.255.128 192.168.100.128
ip http server
!


What am I doing wrong?????????


 
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Paul Cocker
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Posts: n/a
 
      01-07-2005
Don't think you need the route in there (the gateway looks wrong to me
anyhow).

Also I think you'd need

ip subnet-zero

so that you can use the 255.255.255.128 subnet.




"thetownrecluse" <(E-Mail Removed)> wrote in message
news:9zBDd.251$(E-Mail Removed) k.net...
> This is an education situation. I believe I can do this, but not sure
>
> I have multiple machines on a 192.168.100.x switch. All addresses are
> static.
>
> For learning purposes I wanted to insert a router between the switch and
> one of the computers.
>
> I have subnetted the address space in half with mask 255.255.255.128 on
> the machines. I have that up and running.
>
> The router has one interface at 192.168.100. 7 255.255.255.128 and the
> other at 192.168.100.130 255.255.255.128.
>
> I can ping all network addresses from the router. From 192.168.100.132
> address I can ping the 192.168.100.130.
>
> interface Ethernet0
> ip address 192.168.100.130 255.255.255.12
> no ip route-cache
> no ip mroute-cache
> !
> interface Ethernet1
> ip address 192.168.100.7 255.255.255.128
> no ip route-cache
> no ip mroute-cache
> !
> .
> .
> .
> .
> ip classless
> ip route 192.168.100.0 255.255.255.128 192.168.100.128
> ip http server
> !
>
>
> What am I doing wrong?????????
>



 
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thetownrecluse
Guest
Posts: n/a
 
      01-07-2005
These are additional settings in the config. I did not add these. They
just showed up during the remainder of the terminal configuration. Please
stick with me until this works I will be eternally grateful.

!
ip subnet-zero
no ip routing

--------------------------------------------------------------------------------------------------------------------------

"Paul Cocker" <(E-Mail Removed)> wrote in message
news:crmpa2$ha3$(E-Mail Removed)...
> Don't think you need the route in there (the gateway looks wrong to me
> anyhow).
>
> Also I think you'd need
>
> ip subnet-zero
>
> so that you can use the 255.255.255.128 subnet.
>
>
>
>
> "thetownrecluse" <(E-Mail Removed)> wrote in message
> news:9zBDd.251$(E-Mail Removed) k.net...
>> This is an education situation. I believe I can do this, but not sure
>>
>> I have multiple machines on a 192.168.100.x switch. All addresses are
>> static.
>>
>> For learning purposes I wanted to insert a router between the switch and
>> one of the computers.
>>
>> I have subnetted the address space in half with mask 255.255.255.128 on
>> the machines. I have that up and running.
>>
>> The router has one interface at 192.168.100. 7 255.255.255.128 and the
>> other at 192.168.100.130 255.255.255.128.
>>
>> I can ping all network addresses from the router. From 192.168.100.132
>> address I can ping the 192.168.100.130.
>>
>> interface Ethernet0
>> ip address 192.168.100.130 255.255.255.12
>> no ip route-cache
>> no ip mroute-cache
>> !
>> interface Ethernet1
>> ip address 192.168.100.7 255.255.255.128
>> no ip route-cache
>> no ip mroute-cache
>> !
>> .
>> .
>> .
>> .
>> ip classless
>> ip route 192.168.100.0 255.255.255.128 192.168.100.128
>> ip http server
>> !
>>
>>
>> What am I doing wrong?????????
>>

>
>



 
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Paul Cocker
Guest
Posts: n/a
 
      01-07-2005
"thetownrecluse" <(E-Mail Removed)> wrote in message
news8CDd.410$(E-Mail Removed) k.net...
> These are additional settings in the config. I did not add these. They
> just showed up during the remainder of the terminal configuration. Please
> stick with me until this works I will be eternally grateful.
>
> !
> ip subnet-zero
> no ip routing
>
> --------------------------------------------------------------------------------------------------------------------------
>
> "Paul Cocker" <(E-Mail Removed)> wrote in message
> news:crmpa2$ha3$(E-Mail Removed)...
>> Don't think you need the route in there (the gateway looks wrong to me
>> anyhow).
>>
>> Also I think you'd need
>>
>> ip subnet-zero
>>
>> so that you can use the 255.255.255.128 subnet.
>>
>>
>>
>>
>> "thetownrecluse" <(E-Mail Removed)> wrote in message
>> news:9zBDd.251$(E-Mail Removed) k.net...
>>> This is an education situation. I believe I can do this, but not sure
>>>
>>> I have multiple machines on a 192.168.100.x switch. All addresses are
>>> static.
>>>
>>> For learning purposes I wanted to insert a router between the switch and
>>> one of the computers.
>>>
>>> I have subnetted the address space in half with mask 255.255.255.128 on
>>> the machines. I have that up and running.
>>>
>>> The router has one interface at 192.168.100. 7 255.255.255.128 and the
>>> other at 192.168.100.130 255.255.255.128.
>>>
>>> I can ping all network addresses from the router. From 192.168.100.132
>>> address I can ping the 192.168.100.130.
>>>
>>> interface Ethernet0
>>> ip address 192.168.100.130 255.255.255.12
>>> no ip route-cache
>>> no ip mroute-cache
>>> !
>>> interface Ethernet1
>>> ip address 192.168.100.7 255.255.255.128
>>> no ip route-cache
>>> no ip mroute-cache
>>> !
>>> .
>>> .
>>> .
>>> .
>>> ip classless
>>> ip route 192.168.100.0 255.255.255.128 192.168.100.128
>>> ip http server
>>> !
>>>
>>>
>>> What am I doing wrong?????????
>>>

>>
>>

>
>


no ip routing doesn't sound right.

try

conf t
ip routing

also get rid of the original route

no ip route 192.168.100.0 255.255.255.128 192.168.100.128


I'm a beginner myself so this might be wrong!


 
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Peter
Guest
Posts: n/a
 
      01-08-2005
Hi Paul,

> Don't think you need the route in there (the gateway looks wrong to me
> anyhow).


Yes, the route statement should point to a valid Next Hop. It does not
appear to be doing that.

You also need a Route statement for the other subnet, again pointing
to a valid next hop.

> Also I think you'd need
>
> ip subnet-zero


Nope, that may be required if the network addresses were something like
192.168.0.x (IE the 3rd element was a 0 and you were using class C
masks)...


>>I can ping all network addresses from the router. From 192.168.100.132
>>address I can ping the 192.168.100.130.


Provided a Router interface is UP/UP, you should be able to PING all
directly connected devices, but to communicate from devices on one
Router interface THROUGH the router to devices on the other interface,
you need to tell the router what to do with the traffic that comes
into the Router from that interface, AND the reverse flow.

>>ip route 192.168.100.0 255.255.255.128 192.168.100.128


I suspect this should really be -
ip route 192.168.100.0 255.255.255.128 ethernet1

and if you have no other route statements you also need -
ip route 192.168.100.128 255.255.255.128 ethernet0
to cover the reverse direction.

Cheers..........pk.

 
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Tom
Guest
Posts: n/a
 
      01-08-2005

> Provided a Router interface is UP/UP, you should be able to PING all
> directly connected devices, but to communicate from devices on one
> Router interface THROUGH the router to devices on the other interface,
> you need to tell the router what to do with the traffic that comes
> into the Router from that interface, AND the reverse flow.
>
> >>ip route 192.168.100.0 255.255.255.128 192.168.100.128

>
> I suspect this should really be -
> ip route 192.168.100.0 255.255.255.128 ethernet1
>
> and if you have no other route statements you also need -
> ip route 192.168.100.128 255.255.255.128 ethernet0
> to cover the reverse direction.
>
> Cheers..........pk.
>


The router does not need any static routes for networks that are directly
connected.


 
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Tom
Guest
Posts: n/a
 
      01-08-2005

> I can ping all network addresses from the router. From 192.168.100.132
> address I can ping the 192.168.100.130.


I presume that your issue is that 192.168.100.132 can only ping
192.168.100.130 but nothing else? Does this PC have a default route or a
static route so that it knows how to get to networks not in its own range?


> interface Ethernet0
> ip address 192.168.100.130 255.255.255.12
> no ip route-cache
> no ip mroute-cache
> !
> interface Ethernet1
> ip address 192.168.100.7 255.255.255.128
> no ip route-cache
> no ip mroute-cache
> !
> .
> .
> .
> .
> ip classless
> ip route 192.168.100.0 255.255.255.128 192.168.100.128
> ip http server
> !


This static is not needed and is wrong anyway.

>
> What am I doing wrong?????????
>


As above!


 
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Paul Cocker
Guest
Posts: n/a
 
      01-08-2005
>
>> Also I think you'd need
>>
>> ip subnet-zero

>
> Nope, that may be required if the network addresses were something like
> 192.168.0.x (IE the 3rd element was a 0 and you were using class C
> masks)...


I think you've been misinformed. 192.168.0.0 255.255.255.128 breaks down
into two subnets

host broadcast range
192.168.0.0 192.168.0.127 192.168.0.1-192.168.0.126
192.168.0.128 192.168.0.255 192.168.0.129-192.168.0.254

The top one is the "all zero's" subnet and the bottom one the "all 1's".
Valid subnets are 2^1 -2 = 0

Only if you use ip subnet-zero are you allowed to use the top and bottom
subnets - in this case both of them.

Before the use of ip subnet-zero you'd have to break it down to
255.255.255.192

giving you

host broadcast range
192.168.0.0 192.168.0.63 192.168.0.1-192.168.0.62
192.168.0.64 192.168.0.127 192.168.0.129-192.168.0.126
192.168.0.128 192.168.0.191 192.168.0.129-192.168.0.190
192.168.0.192 192.168.0.255 192.168.0.193-192.168.0.254

Where the top and bottom subnets are invalid and you'd only get the middle
two. Very wasteful obviously.

If I've misunderstood this please let me know cause it means I need to hit
the books again!


 
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Peter
Guest
Posts: n/a
 
      01-08-2005
Hi Paul,

>>>Also I think you'd need
>>>
>>>ip subnet-zero

>>
>>Nope, that may be required if the network addresses were something like
>>192.168.0.x (IE the 3rd element was a 0 and you were using class C
>>masks)...

>
>
> I think you've been misinformed. 192.168.0.0 255.255.255.128 breaks down
> into two subnets


If you look at the original section of config that was posted -

> interface Ethernet0
> ip address 192.168.100.130 255.255.255.12
> no ip route-cache
> no ip mroute-cache
> !
> interface Ethernet1
> ip address 192.168.100.7 255.255.255.128
> no ip route-cache
> no ip mroute-cache


then he is using 2 subnets, both based on 192.168.100.x, so "ip
subnet-zero" does not enter into this particular configuration.

Cheers...........pk.

 
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Peter
Guest
Posts: n/a
 
      01-08-2005
Hi Tom,

>>Provided a Router interface is UP/UP, you should be able to PING all
>>directly connected devices, but to communicate from devices on one
>>Router interface THROUGH the router to devices on the other interface,
>>you need to tell the router what to do with the traffic that comes
>>into the Router from that interface, AND the reverse flow.
>>
>>
>>>>ip route 192.168.100.0 255.255.255.128 192.168.100.128

>>
>>I suspect this should really be -
>>ip route 192.168.100.0 255.255.255.128 ethernet1
>>
>>and if you have no other route statements you also need -
>>ip route 192.168.100.128 255.255.255.128 ethernet0
>>to cover the reverse direction.
>>
>>Cheers..........pk.
>>

>
>
> The router does not need any static routes for networks that are directly
> connected.


Correct, the ROUTER doesn't need any static routes for directly
connected networks, but devices EXTERNAL to the Router (IE those
devices that need to TRANSIT the Router) do. The original post
suggested (although it was not explicitly stated) that there was no
return path provided in the config.

This is because any traffic generated FROM the Router itself uses the
IP address of the output interface as its SOURCE address (unless you
use an extended PING where you can explicitly specify it), and it just
has to do an ARP for the target, so it does not need a specific route
to proceed.

Traffic that enters the Router from an external device DOES need a
specific route for the Router to be able to determine the interface to
use when it exits the Router.

Cheers.................pk.

 
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