1 | .\" Copyright (c) 1995 |
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2 | .\" Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved. |
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3 | .\" |
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4 | .\" Redistribution and use in source and binary forms, with or without |
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5 | .\" modification, are permitted provided that the following conditions |
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6 | .\" are met: |
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7 | .\" 1. Redistributions of source code must retain the above copyright |
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8 | .\" notice, this list of conditions and the following disclaimer. |
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9 | .\" 2. Redistributions in binary form must reproduce the above copyright |
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10 | .\" notice, this list of conditions and the following disclaimer in the |
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11 | .\" documentation and/or other materials provided with the distribution. |
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12 | .\" 3. All advertising materials mentioning features or use of this software |
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13 | .\" must display the following acknowledgement: |
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14 | .\" This product includes software developed by Bill Paul. |
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15 | .\" 4. Neither the name of the author nor the names of any co-contributors |
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16 | .\" may be used to endorse or promote products derived from this software |
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17 | .\" without specific prior written permission. |
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18 | .\" |
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19 | .\" THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND |
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20 | .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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21 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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22 | .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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23 | .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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24 | .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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25 | .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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26 | .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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27 | .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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28 | .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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29 | .\" SUCH DAMAGE. |
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30 | .\" |
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31 | .\" $Id$ |
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32 | .\" |
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33 | .Dd April 12, 1995 |
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34 | .Dt ETHERS 3 |
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35 | .Os FreeBSD 2.1 |
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36 | .Sh NAME |
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37 | .Nm ethers , |
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38 | .Nm ether_line , |
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39 | .Nm ether_aton , |
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40 | .Nm ether_ntoa , |
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41 | .Nm ether_ntohost , |
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42 | .Nm ether_hostton |
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43 | .Nd Ethernet address conversion and lookup routines |
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44 | .Sh SYNOPSIS |
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45 | .Fd #include <sys/types.h> |
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46 | .Fd #include <sys/socket.h> |
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47 | .Fd #include <net/ethernet.h> |
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48 | .Ft int |
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49 | .Fn ether_line "char *l" "struct ether_addr *e" "char *hostname" |
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50 | .Ft struct ether_addr * |
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51 | .Fn ether_aton "char *a" |
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52 | .Ft char * |
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53 | .Fn ether_ntoa "struct ether_addr *n" |
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54 | .Ft int |
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55 | .Fn ether_ntohost "char *hostname" "struct ether_addr *e" |
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56 | .Ft int |
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57 | .Fn ether_hostton "char *hostname" "struct ether_addr *e" |
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58 | .Sh DESCRIPTION |
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59 | These functions operate on ethernet addresses using an |
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60 | .Ar ether_addr |
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61 | structure, which is defined in the header file |
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62 | .Aq Pa netinet/if_ether.h : |
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63 | .Bd -literal -offset indent |
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64 | /* |
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65 | * The number of bytes in an ethernet (MAC) address. |
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66 | */ |
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67 | #define ETHER_ADDR_LEN 6 |
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68 | |
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69 | /* |
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70 | * Structure of a 48-bit Ethernet address. |
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71 | */ |
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72 | struct ether_addr { |
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73 | u_char octet[ETHER_ADDR_LEN]; |
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74 | }; |
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75 | .Ed |
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76 | .Pp |
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77 | The function |
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78 | .Fn ether_line |
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79 | scans |
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80 | .Ar l , |
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81 | an |
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82 | .Tn ASCII |
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83 | string in |
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84 | .Xr ethers 5 |
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85 | format and sets |
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86 | .Ar e |
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87 | to the ethernet address specified in the string and |
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88 | .Ar h |
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89 | to the hostname. This function is used to parse lines from |
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90 | .Pa /etc/ethers |
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91 | into their component parts. |
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92 | .Pp |
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93 | The |
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94 | .Fn ether_aton |
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95 | function converts an |
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96 | .Tn ASCII |
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97 | representation of an ethernet address into an |
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98 | .Ar ether_addr |
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99 | structure. Likewise, |
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100 | .Fn ether_ntoa |
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101 | converts an ethernet address specified as an |
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102 | .Ar ether_addr |
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103 | structure into an |
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104 | .Tn ASCII |
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105 | string. |
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106 | .Pp |
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107 | The |
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108 | .Fn ether_ntohost |
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109 | and |
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110 | .Fn ether_hostton |
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111 | functions map ethernet addresses to their corresponding hostnames |
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112 | as specified in the |
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113 | .Pa /etc/ethers |
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114 | database. |
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115 | .Fn ether_ntohost |
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116 | converts from ethernet address to hostname, and |
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117 | .Fn ether_hostton |
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118 | converts from hostname to ethernet address. |
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119 | .Sh RETURN VALUES |
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120 | .Fn ether_line |
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121 | returns zero on success and non-zero if it was unable to parse |
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122 | any part of the supplied line |
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123 | .Ar l . |
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124 | It returns the extracted ethernet address in the supplied |
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125 | .Ar ether_addr |
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126 | structure |
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127 | .Ar e |
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128 | and the hostname in the supplied string |
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129 | .Ar h . |
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130 | .Pp |
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131 | On success, |
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132 | .Fn ether_ntoa |
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133 | returns a pointer to a string containing an |
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134 | .Tn ASCII |
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135 | representation of an ethernet address. If it is unable to convert |
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136 | the supplied |
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137 | .Ar ether_addr |
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138 | structure, it returns a |
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139 | .Dv NULL |
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140 | pointer. Likewise, |
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141 | .Fn ether_aton |
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142 | returns a pointer to an |
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143 | .Ar ether_addr |
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144 | structure on success and a |
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145 | .Dv NULL |
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146 | pointer on failure. |
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147 | .Pp |
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148 | The |
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149 | .Fn ether_ntohost |
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150 | and |
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151 | .Fn ether_hostton |
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152 | functions both return zero on success or non-zero if they were |
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153 | unable to find a match in the |
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154 | .Pa /etc/ethers |
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155 | database. |
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156 | .Sh NOTES |
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157 | The user must insure that the hostname strings passed to the |
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158 | the |
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159 | .Fn ether_line , |
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160 | .Fn ether_ntohost |
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161 | and |
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162 | .Fn ether_hostton |
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163 | functions are large enough to contain the returned hostnames. |
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164 | .Sh NIS INTERACTION |
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165 | If the |
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166 | .Pa /etc/ethers |
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167 | contains a line with a single + in it, the |
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168 | .Fn ether_ntohost |
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169 | and |
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170 | .Fn ether_hostton |
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171 | functions will attempt to consult the NIS |
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172 | .Pa ethers.byname |
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173 | and |
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174 | .Pa ethers.byaddr |
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175 | maps in addition to the data in the |
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176 | .Pa /etc/ethers |
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177 | file. |
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178 | .Sh SEE ALSO |
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179 | .Xr yp 4 , |
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180 | .Xr ethers 5 |
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181 | .Sh BUGS |
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182 | .Pp |
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183 | The |
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184 | .Fn ether_aton |
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185 | and |
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186 | .Fn ether_ntoa |
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187 | functions returns values that are stored in static memory areas |
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188 | which may be overwritten the next time they are called. |
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189 | .Sh HISTORY |
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190 | This particular implementation of the |
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191 | .Nm ethers |
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192 | library functions were written for and first appeared in |
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193 | .Fx 2.1 . |
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