4 ms·

Here are a couple I use: - How many hosts are there in a /23 network? - Estimate ping time from your workstation to your local gateway? www.google.com? Server

• tyingq 10y ago
  "How many hosts are there in a /23 network?" Having interviewed a lot of sysadmins, I see this trip people up, mostly because the slash/bits network notation isn't taught/documented well. The "memorize a table" approach seems to be common. Most of them, with a bit of prompting, get that an ipv4 is 32 bits, and that a /23 means (32-23==9) 9 bits of host addresses. Most also can figure out what 111111111 is. Some remember to account for the network and broadcast address not being available for hosts.
  • deleted 10y ago
    [deleted]
• falcolas 10y ago
  > How many hosts are there in a /23 network? I've recently learned that this is a bit of a trick question. How many routers are in embedded the /23? How many addresses are reserved for multicast? Are you on AWS VPC, where they reserve even a few more addresses for internal management?
  • dmourati 10y ago
    All of those are good points. But a surprising number of people can't get to the starting point 2^(32-23)=512. I usually subtract 2 and say 510. No IPs are reserved for multicast. Maybe you meant broadcast?