Subnetting Post: 302993570

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Special Forums IP Networking Subnetting Post 302993570 by drysdalk on Saturday 11th of March 2017 07:41:05 AM

03-11-2017

Registered User

Hi,

Firstly, from just looking at a single IP, you can't tell how large the network it's a part of is. You need to know the netmask. So for example, if I had an IP of 192.168.1.10, that doesn't tell you anything at all about how large or small the network I'm a part of is.

But if I tell you the netmask - e.g. 192.168.1.10/24 or 192.168.1.10/255.255.255.0 - then you know it's part of a network of 256 addresses, running from 192.168.1.0 to 192.168.1.255.

If on the other hand I'd told you the netmask was 192.168.1.10/25 or 192.168.1.10/255.255.255.128 - then you'd know it was part of a network of 128 addresses going from 192.168.1.0 to 192.168.1.127.

And again, in every network, the very first address and the very last address are not usable for hosts, as they are reserved for other purposes.

You can also get plenty of other netmasks than the old simple Class A, B, C notation tells you. For instance I could just have easily told you my netmask was 192.168.1.10/28, in which case you'd then be able to calculate that the network I was a part of runs from 192.168.1.0 to 192.168.1.15, and conists of 16 IP addresses.

So just from looking at an IP you can't tell anything about the size of the network. And these days, there are far more netmasks and subnet sizes that are far more common than the old Class A/B/C notation.

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LEARN ABOUT DEBIAN

rlm_ippool_tool

RLM_IPPOOL_TOOL(8)					      System Manager's Manual						RLM_IPPOOL_TOOL(8)

NAME

       rlm_ippool_tool - dump the contents of the FreeRadius ippool database files

SYNOPSIS

       If an ipaddress is specified then that address is used to limit the actions or output.

       rlm_ippool_tool [-a] [-c] [-o] [-v] session-db index-db [ipaddress]

       Mark the entry nasIP/nasPort as having ipaddress

       rlm_ippool_tool -n session-db index-db ipaddress nasIP nasPort

       Update old format database to new.

       rlm_ippool_tool -u session-db new-session-db

DESCRIPTION

       rlm_ippool_tool dumps the contents of the FreeRADIUS ippool databases for analyses or for removal of active (stuck?) entries.

       Or with the -n argument adds a usage entry to the FreeRADIUS ippool databases.

OPTIONS

       -a     Print all active entries.

       -c     Report number of active entries.

       -r     Remove active entries.

       -v     Verbose report of all entries.

       -o     Assume old database format (nas/port pair, not md5 output).

       -n     Mark the entry nasIP/nasPort as having ipaddress.

       -u     Update old format database to new.

EXAMPLES

       Given the syntax in the FreeRadius radiusd.conf:

	       ippool myippool {
		   range-start = 192.168.1.0
		   range-stop = 192.168.1.255
		   [...]
		   session-db = ${raddbdir}/ip-pool.db
		   ip-index = ${raddbdir}/ip-index.db
	       }

       To see the number of active entries in this pool, use:

	       $ rlm_ippool_tool -c ip-pool.db ip-index.db
	       13

       To see all active entries in this pool, use:

	       $ rlm_ippool_tool -a ip-pool.db ip-index.db
	       192.168.1.5
	       192.168.1.82
	       192.168.1.244
	       192.168.1.57
	       192.168.1.120
	       192.168.1.27
	       [...]

       To see all information about the active entries in the use, use:

	       $ rlm_ippool_tool -av ip-pool.db ip-index.db
	       NAS:172.16.1.1 port:0x2e8 - ipaddr:192.168.1.5 active:1 cli:0 num:1
	       NAS:172.16.1.1 port:0x17c - ipaddr:192.168.1.82 active:1 cli:0 num:1
	       NAS:172.16.1.1 port:0x106 - ipaddr:192.168.1.244 active:1 cli:0 num:1
	       NAS:172.16.1.1 port:0x157 - ipaddr:192.168.1.57 active:1 cli:0 num:1
	       NAS:172.16.1.1 port:0x2d8 - ipaddr:192.168.1.120 active:1 cli:0 num:1
	       NAS:172.16.1.1 port:0x162 - ipaddr:192.168.1.27 active:1 cli:0 num:1
	       [...]

       To see only information of one entry, use:

	       $ rlm_ippool_tool -v ip-pool.db ip-index.db 192.168.1.1
	       NAS:172.16.1.1 port:0x90 - ipaddr:192.168.1.1 active:0 cli:0 num:0

       To add an IP address usage entry, use:

	       $ rlm_ippool_tool -n ip-pool.db ip-index.db 192.168.1.1 172.16.1.1 0x90
	       rlm_ippool_tool: Allocating ip to nas/port: 172.16.1.1/144
	       rlm_ippool_tool: num: 1
	       rlm_ippool_tool: Allocated ip 192.168.1.1 to client on nas 172.16.1.1,port 144

SEE ALSO

       radiusd(8)

AUTHORS

       Currently   part   of   the   FreeRADIUS   Project   (http://www.freeradius.org)   Originally   by   Edwin   Groothuis,	 edwin@mavetju.org
       (http://www.mavetju.org)

       Mailing list details are at http://www.freeradius.org/

																RLM_IPPOOL_TOOL(8)

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rlm_ippool_tool