netconf file, broadcast address

[Rashid Hamid]

I need to change the ip address for lan0 manually in /etc/rconfig.d/netconf. Below is the netconf file:

INTERFACE_NAME[0]=lan0
IP_ADDRESS[0]=172.23.32.152
SUBNET_MASK[0]=255.255.240.0
BROADCAST_ADDRESS[0]=172.23.47.255
INTERFACE_STATE[0]=up
DHCP_ENABLE[0]=0
INTERFACE_MODULES[0]=""

I need to change the IP address to
172.23.6.72
255.255.240.0
gateway: 172.23.5.40

Question: What is the broadcast address value? Should I edit manually? If manually edited, what is the new broadcast address?

Thank you very much

[Tvs]

Hi

the new brodcast address : 172.23.15.255

you can manually edit the conf file or you can chage it with ifconfig , set_param network or initial commands.

regards

tvs

[Ramaprasad N]

The network/subnet number is the lowest value numerically in that network/subnet. The
broadcast address is the largest value numerically in that network/subnet. The valid,
assignable addresses in that network are the numbers between the network/subnet number
and the broadcast address.

Algorithm for calculating broadcast address.

Step 1 Write down the IP address in decimal.
Step 2 Write down the mask in decimal.
Step 3 Examine the mask. One of the four octets will have a value besides
255 or 0; otherwise, this would not be considered to be a
â difficultâ case. The octet with the non-255, non-0 value is
considered to be the â interestingâ octet. The other three are
considered â boring.â Write down the number (1, 2, 3, or 4) of the
interesting octet. (For example, mask 255.255.240.0 has an
interesting third octet.)
Step 4 Subtract the maskâ s interesting octetâ s value from 256. Call that
value the multiplier. Write it down.
Step 5 For any boring octets to the left of the interesting octet, copy those
octets from the subnet onto a new line on your paper, leaving
space for the remaining octets. This line will be where you record
the broadcast address.
Step 6 For any boring octets to the right of the interesting octet, record a
value of 255 in the broadcast address (the same number as in Step
5.) One of the four octets should still be emptyâ the interesting
octet.
Step 7 Examine the interesting octet of the original IP address. Discover
the multiple of the multiplier closest to this number but greater
than the number. Subtract 1 from this multiple. Write down this
value (1 less than the integer multiple of the multiplier) in the
interesting octet of the broadcast address.

Broadcase address for your network, to the best of my understanding is 172.23.15.255

[Senthil Kumar .A_1]

Hi Rashid,


Firstly,disable subnet mask checking (otherwise it might fail to take the broadcast address i have calculated for your new ip address):

# ndd -set /dev/ip ip_check_subnet_addr 0

To make permanent, edit /etc/rc.config.d/nddconf:
TRANSPORT_NAME[0]=ip
NDD_NAME[0]=ip_check_subnet_addr
NDD_VALUE[0]=0


ONCE the above steps were executed , set your broadcast address as follows in your nteconf file manually and reboot the server.

172.23.15.255

Regards,
Senthil Kumar .A

P.S : For more info refer the following link,

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=900250

[Bejoy C Alias]

10101100.00010111.00000110.01001000 =172.23.6.72
11111111.11111111.11110000.00000000 =255.255.240.0

Mask ur host part <----------->
which will become
10101100.00010111.00001111.11111111 =172.23.15.255

172.23.15.255 is the broadcast address

[Asif Sharif]

http://docs.hp.com/en/B2355-90796/