12/24/2001 5:35pm Monday Well said ----- Original Message ----- From: ""Mike"" Newsgroups: groupstudy.cisco Sent: Monday, December 24, 2001 5:35 PM Subject: Re: IP classless command [7:30056]
> The best way to explain IP classless is to explain how a router works with > "no ip classless". Suppose you have a router with a static route configured > to 10.1.1.0/24 out some interface and you also have a default gateway > configured. Again, ip classless is disabled, "no ip classless". > > A packet comes into the router destined for 10.1.1.2, the router looks at > the routing table, sees the static route and forwards as expected. > > A packet comes into the router destined for 11.x.x.x, the router looks at > the routing table, sees the default gateway and forwards as expected. > > A packet comes into the router destined for 10.10.10.1, you would expect the > router to forward the packet via the default gateway. However, because the > router is operting in "classful mode", the router drops the packet rather > then using the default gateway. This is because the router is in the same > classful network as the 10.1.1.0/24 network used for the static route. > > If the "ip classless" command was used, the dropped packet would actually be > forwarded via the default gateway. There really is no reason not to use "ip > classless" on all router configurations. > > Mike > > > > ""Hunt Lee"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Can anyone please explain to me what is "ip classless" used for? I looked > > it up on the Caslow book, and it states that by enabling IP classless, it > > allows one to override the contiguous subnet rule and allow the router to > > look for the longest match beyond the listed subnets. > > > > But I still don't understand what it means? Can anyone give me some > > examples? > > > > Thanks in advance. > > > > Best Regards, > > Hunt Lee > > IP Solution Analyst > > Cable & Wireless Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=30063&t=30056 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
