RE: NAT concepts [7:37815]
Dear Paul: according to my perception:when we have a pool of addresses hired from certain operator/internic we configure it to be used statically or through NAT.we may not need to use all IP addresses for nAT lonely but some of them can be used for static trans.thats why we describe the start IP abbresses and end ip Address.NAT function should know the subnet mask coz when a packet from private addresse comes in it is translated thru NAT with subnetmask attached .Subnetmask in this case will help the routing of the packet when it comes back to the oronating system through different routers.Plus in all IP address scenarios we need to mention IP adress with mask as router do the AND operation to extract original IP address.It would not have been possible for any router in the path to extract orinal network without having subnetmask i hope u understand whay i m saying Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=37840t=37815 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: NAT concepts [7:37815]
As far as I can tell this is another one of those Cisco quirks. Unless Cisco plan for the future a mechanism whereby the route to the NAT pool is dynamically advertised, then the subnet mask has no *real* function. IMO while routes to the pool are statically defined and then redist, it remains a mere annoyance. rgds Marc saleem bilal wrote: Dear Paul: according to my perception:when we have a pool of addresses hired from certain operator/internic we configure it to be used statically or through NAT.we may not need to use all IP addresses for nAT lonely but some of them can be used for static trans.thats why we describe the start IP abbresses and end ip Address.NAT function should know the subnet mask coz when a packet from private addresse comes in it is translated thru NAT with subnetmask attached .Subnetmask in this case will help the routing of the packet when it comes back to the oronating system through different routers.Plus in all IP address scenarios we need to mention IP adress with mask as router do the AND operation to extract original IP address.It would not have been possible for any router in the path to extract orinal network without having subnetmask i hope u understand whay i m saying Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=37844t=37815 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: NAT concepts [7:37815]
Yea it's a sanity check alright. If you are not alreay insane, NAT will do
it. Now to figure out why every time I try to use NAT on the outside in
version 12.1.13 it causes the router to reboot
Thanks!
Paul
- Original Message -
From: Lupi, Guy
To: 'Paul Borghese' ;
Sent: Sunday, March 10, 2002 6:31 PM
Subject: RE: NAT concepts [7:37815]
Found this on CCO, I assume the prefix would be the same concept, a sanity
check. Link is at the bottom, HTH.
Q. Why do I need to specify a subnet mask when configuring a NAT address
pool?
A. The subnet mask is used to sanity-check the addresses allocated from
the
pool (so we don't allocate the subnet broadcast address, for example). The
subnet mask must match the size of the subnet into which you are
translating.
http://www.cisco.com/warp/public/cc/pd/iosw/ioft/iofwft/prodlit/iosnt_qp.htm
~-Original Message-
~From: Paul Borghese [mailto:[EMAIL PROTECTED]]
~Sent: Sunday, March 10, 2002 5:49 PM
~To: [EMAIL PROTECTED]
~Subject: NAT concepts [7:37815]
~
~
~Hi,
~
~I am trying to conceptually understand the NAT command:
~
~ip nat pool name start-ip end-ip {netmask netmask | prefix-length
~prefix-length}[type rotary]
~
~Why do you need to specify the netmask or prefix-length of the
~network? You
~are already specifying the IP range.
~
~The NAT function should not need to know the netmask of the
~network. The
~address range does not appear in the forwarding table so it
~does not seem to
~be used for routing.
~
~Paul Borghese
~
~
~
~
~Report misconduct
~and Nondisclosure violations to [EMAIL PROTECTED]
~
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7i=37849t=37815
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NAT concepts [7:37815]
Hi,
I am trying to conceptually understand the NAT command:
ip nat pool name start-ip end-ip {netmask netmask | prefix-length
prefix-length}[type rotary]
Why do you need to specify the netmask or prefix-length of the network? You
are already specifying the IP range.
The NAT function should not need to know the netmask of the network. The
address range does not appear in the forwarding table so it does not seem to
be used for routing.
Paul Borghese
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7i=37815t=37815
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RE: NAT concepts [7:37815]
Found this on CCO, I assume the prefix would be the same concept, a sanity
check. Link is at the bottom, HTH.
Q. Why do I need to specify a subnet mask when configuring a NAT address
pool?
A. The subnet mask is used to sanity-check the addresses allocated from the
pool (so we don't allocate the subnet broadcast address, for example). The
subnet mask must match the size of the subnet into which you are
translating.
http://www.cisco.com/warp/public/cc/pd/iosw/ioft/iofwft/prodlit/iosnt_qp.htm
~-Original Message-
~From: Paul Borghese [mailto:[EMAIL PROTECTED]]
~Sent: Sunday, March 10, 2002 5:49 PM
~To: [EMAIL PROTECTED]
~Subject: NAT concepts [7:37815]
~
~
~Hi,
~
~I am trying to conceptually understand the NAT command:
~
~ip nat pool name start-ip end-ip {netmask netmask | prefix-length
~prefix-length}[type rotary]
~
~Why do you need to specify the netmask or prefix-length of the
~network? You
~are already specifying the IP range.
~
~The NAT function should not need to know the netmask of the
~network. The
~address range does not appear in the forwarding table so it
~does not seem to
~be used for routing.
~
~Paul Borghese
~
~
~
~
~Report misconduct
~and Nondisclosure violations to [EMAIL PROTECTED]
~
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7i=37820t=37815
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