Results 1 to 1 of 1
04-21-2009, 10:01 AM #1New User
- Join Date
- Apr 2009
Private address range network mask error
I've read Chapters 1-3 and got it that the private IP address range 172.16.0.0 - 172.31.255.255 has the network mask of /16. It is also being implied by review questions.
E.g., see Written lab 3.3 asks to detail the IP address 172.31.254.12 /24.
The book gives the following answer:
IP Addr Addr.class Subnet/Host bits #of subnets #of hosts
172.31.254.12 /24 B 8/8 256 254
Review question #4 in Chapter 3:The network address of 172.16.0.0 /19 provides how many subnets and hosts?
The book gives the following answer:According to http://www.ietf.org/rfc/rfc1918.txt:4. F. A CIDR address of /19 is 255.255.224.0. This is a Class B address, so that is only 3 subnet
bits, but it provides 13 host bits, or 8 subnets, each with 8,190 hosts.The Internet Assigned Numbers Authority (IANA) has reserved theAs you see the correct mask for range in subject is /12 not /16.
following three blocks of the IP address space for private internets:
10.0.0.0 - 10.255.255.255 (10/8 prefix)
172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
192.168.0.0 - 192.168.255.255 (192.168/16 prefix)
We will refer to the first block as "24-bit block", the second as
"20-bit block", and to the third as "16-bit" block.
That means answers should be different.
Review question #4 should say: "This is a 20-bit block of private IP address address with /12 network mask (255.224.0.0), so there are 7 subnet
bits, it provides 13 host bits, or 128 subnets, each with 8,190 hosts."
Same applies for Lab 3.3.
Mr.Lammle, could you comment please?
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By myccna in forum CCENT Chapter 3: TCP/IPReplies: 5Last Post: 09-12-2015, 10:21 AM
By kuband12 in forum CCENT Chapter 5: VLSM and SummarizationReplies: 0Last Post: 02-17-2014, 09:40 AM
By TorontoCCNAStudent in forum RoutingReplies: 3Last Post: 07-05-2011, 02:24 AM
By cattleman in forum AnnouncementsReplies: 4Last Post: 01-27-2010, 02:45 AM
By doshi.devang in forum InternetworkingReplies: 1Last Post: 01-09-2010, 04:57 PM