Appendix C. Useful Network Tables

Table C.1. Internet Address Classes

Class	Lowest	Highest	Network Bits	Host Bits
A	0.0.0.0	127.255.255.255	7	24
B	128.0.0.0	191.255.255.255	14	16
C	192.0.0.0	223.255.255.255	21	8
D	224.0.0.0	239.255.255.255	28	N/A
E	240.0.0.0	247.255.255.255	27	N/A

Table C.2. Netmask Values by IP Class

Class	Lowest	Highest	Netmask
A	0.0.0.0	127.255.255.255	255.0.0.0
B	128.0.0.0	191.255.255.255	255.255.0.0
C	192.0.0.0	223.255.255.255	255.255.255.0

Table C.3. Private IP Number Allocations

Class	Lowest	Highest	Netmask
A	10.0.0.0	10.255.255.255	255.0.0.0
B	172.16.0.0	172.31.255.255	255.255.0.0
C	192.168.0.0	192.168.255.255	255.255.255.0

Table C.4. Amateur Radio Reserved IP Numbers

Class	Lowest	Highest	Netmask
A	44.0.0.0	44.255.255.255	255.0.0.0

Table C.5. The /proc/sys/net/ipv4/tcp_stdurg Settings

Value	Interpretation
0	BSD Interpretation (Linux default)
1	RFC793 interpretation

Table C.6. The /etc/inetd.conf Configuration Record

Field #	Description	Example
1	Internet service name	telnet (this may also be a port number)
2	Socket type	stream or dgram
3	Protocol	tcp or udp
4	Flags	nowait or wait
5	UserID to use	root or nobody
6	Pathname of executable	/usr/sbin/in.telnetd
7	Server arguments	in.telnetd