05-18-2011 09:45 AM - edited 03-06-2019 05:07 PM
Dear Experts,
I am advertising an IP range 175.106.20.0/20 on the Internet for my company. I would like to divide this range into smaller chunks to easily manage it. Please advice any software or a utility which can give me the exact mask as well as the chunk ranges to advertise.
Thank You.
Solved! Go to Solution.
05-18-2011 12:01 PM
Just to add to John's post.
Subnet calculators are useful for working out ranges with a specific subnet mask applied but it is really up to you to decide how you want to break it down ie. 175.106.20.0 255.255.240.0 could be subnetted in many ways to give many different individual subnets so you need to start with an idea of how many subnets you need and how many hosts per subnet you need.
Bear in mind also that there are limits on how small a range can be advertised to the internet.
Jon
05-26-2011 09:38 AM
Adding to Jon, that single /20 block is a huge block , you could brake for example to 16 /24 networks, 254 ip host per /24 network.
Example :
175.106.16.0/24
172.106.17.0/24
x.x.18.x/24
x.x.19.x/24
x.x.20.x/24
x.x.21.x/24
and so on...
The key to keep in mind is how you would want these blocks be announce, I suggest you do thorough analysis of your company internet architecture , present and future and come up with proper allocation of your blocks to minimize the re-addressing and re-advertizing nightmares.
another example could be out of a /24 off your /20 block say 175.106.18.0/24 can be further brake down to smaller blocks to be announced in various sites , again , like Jon indicated in his post, it all depends on your company's requirements for example such as branch offices having their own internet ISP where you may have public web servers requiring public IP addresses, or even requiring public IP pool blocks for various purposes etc..
Another example of further braking down your /24 you can have two /26's off that 175.106.18.0/24 that is still part of the /20 network , which could be 175.106.18.0/25 and 175.106.18.128/25 allowing 126 public IP addresses per network , and have these blocks being announced by different office branches that have their own ISP , this is just an example , or announce both and separate the routing at the perimeter device, there are so many variables in allocating and braking down that huge /20 block.
Here is a freeware subnet cal if you are still looking for one.
my 2 censt
Regards
06-28-2011 05:37 AM
how many breakout points to the Internet do you have?
when advertising to the internet -- i recommend you advertise the whole range /20 (via BGP) to your transit provider.
Internally you should use an IGP and split (and do whatever you want) without affecting your global internet route.
05-18-2011 10:28 AM
They are called subnet calculator's. I would recommend googling for one. There are plenty of free ones out there on the internet. I would try looking for the one that best fits your purpose.
05-18-2011 12:01 PM
Just to add to John's post.
Subnet calculators are useful for working out ranges with a specific subnet mask applied but it is really up to you to decide how you want to break it down ie. 175.106.20.0 255.255.240.0 could be subnetted in many ways to give many different individual subnets so you need to start with an idea of how many subnets you need and how many hosts per subnet you need.
Bear in mind also that there are limits on how small a range can be advertised to the internet.
Jon
05-26-2011 12:54 AM
Thank you for your reply.
Kind regards.
05-26-2011 09:38 AM
Adding to Jon, that single /20 block is a huge block , you could brake for example to 16 /24 networks, 254 ip host per /24 network.
Example :
175.106.16.0/24
172.106.17.0/24
x.x.18.x/24
x.x.19.x/24
x.x.20.x/24
x.x.21.x/24
and so on...
The key to keep in mind is how you would want these blocks be announce, I suggest you do thorough analysis of your company internet architecture , present and future and come up with proper allocation of your blocks to minimize the re-addressing and re-advertizing nightmares.
another example could be out of a /24 off your /20 block say 175.106.18.0/24 can be further brake down to smaller blocks to be announced in various sites , again , like Jon indicated in his post, it all depends on your company's requirements for example such as branch offices having their own internet ISP where you may have public web servers requiring public IP addresses, or even requiring public IP pool blocks for various purposes etc..
Another example of further braking down your /24 you can have two /26's off that 175.106.18.0/24 that is still part of the /20 network , which could be 175.106.18.0/25 and 175.106.18.128/25 allowing 126 public IP addresses per network , and have these blocks being announced by different office branches that have their own ISP , this is just an example , or announce both and separate the routing at the perimeter device, there are so many variables in allocating and braking down that huge /20 block.
Here is a freeware subnet cal if you are still looking for one.
my 2 censt
Regards
06-28-2011 05:37 AM
how many breakout points to the Internet do you have?
when advertising to the internet -- i recommend you advertise the whole range /20 (via BGP) to your transit provider.
Internally you should use an IGP and split (and do whatever you want) without affecting your global internet route.
06-28-2011 05:44 AM
Thank you all, it has been sorted out.
Kind Regards,
Ahmed Ejaz
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