Question regarding building a network from packettracer (from scratch)...

gbdavidxgbdavidx Member Posts: 840


I am trying to practice for CCNA however, I am stuck at building the initial network from scratch. I have my networks as follows

10.0.0.0 - 10.0.255.255
10.1.0.0 - 10.1.255.255
10.2.0.0 - 10.2.255.255
10.3.0.0 - 10.3.255.255
ect. I am using a 255.0.0.0 should I not be using this?

I am getting an error when trying to assign the IP addresses bad mask/30 for address 10.0.0.4

What does this mean? Do i need to use VLSM?

These are my recent commands

SHSS(config-if)#ip address 10.0.0.2 255.255.255.252
SHSS(config-if)#exit
SHSS(config)#int
SHSS(config)#interface s1/2
SHSS(config-if)#ip address 10.0.0.4 255.255.255.252
Bad mask /30 for address 10.0.0.4
SHSS(config-if)#

Comments

  • Ltat42aLtat42a Member Posts: 587 ■■■□□□□□□□
    gbdavidx wrote: »

    These are my recent commands

    SHSS(config-if)#ip address 10.0.0.2 255.255.255.252
    SHSS(config-if)#exit
    SHSS(config)#int
    SHSS(config)#interface s1/2
    SHSS(config-if)#ip address 10.0.0.4 255.255.255.252
    Bad mask /30 for address 10.0.0.4
    SHSS(config-if)#

    The reason you're getting a bad mask error, is because you're trying to assign a network address to the serial interface. This is where you need to know subnetting. For the address & subnet mask 10.0.0.4 255.255.255.252, the only two valid IP's you can use is 10.0.0.5 and 10.0.0.6.
    10.0.0.4 - network address (can't use this)
    10.0.0.5 - valid address
    10.0.0.6 - valid address
    10.0.0.7 - broadcast address (can't use this)

    10.0.0.8/30 - next subnet

    hth
  • tecnodog7tecnodog7 Member Posts: 129
    Can't assign a network address for your interface.

    Go back and review subnetting. Like Ltat42a said, /30 only gives you 2 usable IP address per subnet.
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