I hate dealing with idiot customers who have to have you point out the exact
RFC saying why that's wrong. You're not going to find such a thing, but
rather just knowledge about what the subnet mask is for and what it does.
The biggest problem you get with different masks for hosts that both fit
within the smaller of the two subnet masks is that they have different
broadcasts:
172.16.8.1 255.255.240.0
network address: 172.16.0.0
broadcast: 172.16.15.255
172.16.8.35 255.255.255.240
network address: 172.16.8.32
broadcast: 172.16.8.47
Looking at this, you've got an even bigger problem: 172.16.8.1 isn't on the
same subnet as 172.16.8.35/28 (/28 = 255.255.255.240). They just flat-out
won't (or shouldn't) be able to talk to each other.
Simplest terms, tell the customer that it doesn't follow ip subnetting rules
and shouldn't work. That it might work is just a fluke.
--
Jason Roysdon, CCNA, MCSE, CNA, Network+, A+
List email: [EMAIL PROTECTED]
Homepage: http://jason.artoo.net/
Cisco resources: http://r2cisco.artoo.net/
""Simon Watson"" <[EMAIL PROTECTED]> wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> Hi Guys
>
> I've got a customer who has a VSAT WAN network consisting of Cisco
routers,
> who has for a point to point connection between 2 routers used different
> subnet masks i.e on the interface of one router the IP address is
172.16.8.1
> Mask 255.255.240.0, on the interface of the router at the other end of the
> link an IP address of 172.16.8.35 mask 255.255.255.240. (No dynamic
routing
> protocol is in operation at the moment). For the remote router to send
data
> accross the link a static route has to be configured as 172.16.8.1 is not
in
> it's subnet.
>
> I'm trying to find documents on the web (i.e RFC's) to show to the
customer
> that this subnetting scheme, is unconventional, unadvisable and not
> recommended, and that devices residing on the same network should have the
> same subnet mask.
>
> Can anyone help ????
>
>
> Thanks in advance
>
> Simon CCNP
>
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