1NETMASK(1) Debian Linux NETMASK(1)
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6 netmask - a netmask generation and conversion program
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9 netmask [ options ] spec [ spec ... ]
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12 This program accepts and produces a variety of common network address
13 and netmask formats. Not only can it convert address and netmask nota‐
14 tions, but it will optimize the masks to generate the smallest list of
15 rules. This is very handy if you've ever configured a firewall or
16 router and some nasty network administrator before you decided that
17 base 10 numbers were good places to start and end groups of machines.
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20 -h, --help
21 Print a summary of the options
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23 -v, --version
24 Print the version number
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26 -d, --debug
27 Print status/progress information
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29 -s, --standard
30 Output address/netmask pairs
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32 -c, --cidr
33 Output CIDR format address lists
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35 -i, --cisco
36 Output Cisco style address lists
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38 -r, --range
39 Output ip address ranges
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41 -x, --hex
42 Output address/netmask pairs in hex
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44 -o, --octal
45 Output address/netmask pairs in octal
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47 -b, --binary
48 Output address/netmask pairs in binary
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50 -n, --nodns
51 Disable DNS lookups for addresses
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54 A spec is an address specification, it can look like:
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56 address
57 One address.
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59 address1:address2
60 All addresses from address1 to address2.
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62 address1:+address2
63 All addresses from address1 to address1+address2.
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65 address/mask
66 A group starting at address spanning mask.
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68 An address is an internet network address, it can look like:
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70 ftp.gnu.org
71 An internet hostname.
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73 209.81.8.252
74 A standard dotted quad internet address notation.
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76 100 A decimal number (100 in this case).
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78 0100 An octal number preceded by "0" (64 in this case).
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80 0x100 A hexadecimal number preceded by "0x" (256 in this case).
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82 A mask is a network mask, it can look like:
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84 255.255.224.0
85 A dotted quad netmask (netmask will complain if it is not a
86 valid netmask).
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88 0.0.31.255
89 A Cisco style inverse netmask (with the same checks).
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91 8 The number of bits set to one from the left (CIDR notation).
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93 010 The number of bits set to one from the left in octal.
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95 0x10 The number of bits set to one from the left in hexadecimal.
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98 netmask was written by Robert Stone. Some algorithm design and opti‐
99 mization was provided by Tom Lear. This manual page was written by
100 Robert Stone.
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103 Let me know if you find any. This man page is a bit more simplistic
104 than I'd like, but I've forgotten most of the groff I once knew.
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107 ipchains(1), ipfwadm(8), netstat(8), route(8), routed(8), gated(8),
108 tcpd(8)
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112Debian Project 15 May 1999 NETMASK(1)