I need help with IP configuration. Does anyone know what a /30 is in an ip configuration?

Question

I am a network engineer that hasn't configured a router in about six months and since I got back in the game it seems they have changed things. I recently got my company a fiber internet connection and they sent me the IP configuration information and I have to say I am a bit lost. What does it mean when they send you The IP address at your interface needs to be IP x.x.x.x/30 (x=ip address) for the IP address to assign to your interface? Please help!!!

Answer 1

Choices of address are x.x.x.x+1 or x.x.x.x+2,. Its a 30 bit mask, so you only get 4 possible addresses, of which one is broadcast and another is the subnet ID (neither of which is a useable address).

Answer 2

New engineer, huh? (That's pretty basic stuff, actually -- TCP/IP 101 as it were.) That means a 30 bit subnet mask. Use 255.255.255.252 as your SN mask. The default gateway will be the other useable IP address in that network. So if they gave you 12.208.24.5/30 for your router, the network address is 12.208.24.4, the two useable IP addresses are 12.208.24.5 and 12.208.24.6 and the broadcast address 12.208.24.7. You'd use 12.208.24.5 mask 255.255.255.252 on the router's WAN interface and 12.208.24.6 as the default gateway or gateway of last resort.

The /30 is called CIDR notation and represents the number of bits in the subnet mask. It's a fancy "geek speak" way of expressing the subnet mask with a lot fewer keystrokes. /29 would equate to 255.255.255.248, /28 would be 255.255.255.240, etc. Get the picture?

Answer 3

which company is that i never really seen that before that is totally new to me i will suggest you called the company and ask that.

Answer 4

http://www.chongluo.com/books/microsoft/mellit/index.html?page=extfile%2Fextrain%2Fextrain%2Fch10f.htm