INTELLIGENT WORK FORUMS
FOR COMPUTER PROFESSIONALS

Member Login




Remember Me
Forgot Password?
Join Us!

Come Join Us!

Are you a
Computer / IT professional?
Join Tek-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

Join Tek-Tips
*Tek-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.
Jobs from Indeed

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

Can you use 255.255.255.255 for a subnet mask?

Share

Can you use 255.255.255.255 for a subnet mask?

Can you use 255.255.255.255 for a subnet mask?

(OP)
Had an interview today and did a networking test with 15 questions, was fairly straight forward.

There was one question, which asked which subnet mask you would use to make a printer the only host on a network. So I said 255.255.255.252 - 2 useable hosts, minimum address wastage.

But the guy said I was wrong, and that 255.255.255.255 would be used. Is this true? how if so? thanks

'When all else fails.......read the manual'

RE: Can you use 255.255.255.255 for a subnet mask?

Yes---255.255.255.255 is a single host mask. This is used all the time in adsl.

Burt

RE: Can you use 255.255.255.255 for a subnet mask?

(OP)
Oh well, that's something new for me.

In CCNA the furthest they say you can go is .252!

So how does it work then? What about wire and broadcast addresses?

'When all else fails.......read the manual'

RE: Can you use 255.255.255.255 for a subnet mask?

There are no broadcasts in situations like this, and the address in effect is the wire address. You would not have anything else on the network, like a /30 would. There are certain situations (PPP) that allow a /31---I believe this is Cisco proprietary, though. Just two point to point addresses, no broadcast or wire.

Burt

RE: Can you use 255.255.255.255 for a subnet mask?

Burt is 100% correct.  

The reason that the CCNA says you can only goto .252 is this:

256-252 = 4 ips in that subnet.  You will have your network id , then two usable ips, and finally your broadcast ip.  

I just wanted to explain that a little better for you in case you were not sure.

Gb0mb

........99.9% User Error........

RE: Can you use 255.255.255.255 for a subnet mask?

Also, I remember even in CCNA that when configuring loopback addresses, you should use a /32 mask.

Burt

RE: Can you use 255.255.255.255 for a subnet mask?

I, personally, think that you are both correct.

You can indeed assign a netmask of 255.255.255.255, but if you do that, I would argue that it is no longer a network but a standalone host.


pansophic

RE: Can you use 255.255.255.255 for a subnet mask?

You are correct---I am not arguing that it is not a standalone host. It is.

Burt

RE: Can you use 255.255.255.255 for a subnet mask?

Look at your routing tables and you find that the .255 masks are used if you want to specify routing to a single address only instead of a network block. This is one application for the single mask.

Reply To This Thread

Posting in the Tek-Tips forums is a member-only feature.

Click Here to join Tek-Tips and talk with other members!

Close Box

Join Tek-Tips® Today!

Join your peers on the Internet's largest technical computer professional community.
It's easy to join and it's free.

Here's Why Members Love Tek-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close