1 | DNS Exercise - Delegation |
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2 | ------------------------- |
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3 | |
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4 | In this exercise, we will create a new TLD in our root. |
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5 | for example: MYTLD |
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6 | |
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7 | You will create a master nameservice on your own machine, and someone else |
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8 | will provide slave service. Then you will ask the administrator for the |
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9 | domain above you (dns) to delegate your domain to you. |
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10 | |
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11 | Note: the following should be done as the "root" superuser. |
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12 | |
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13 | Firstly, note that your hostname is configured correctly |
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14 | on your machine. Check that it is configured correctly by |
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15 | using the 'hostname' command - e.g. on pc18.ws.nsrc.org, if you type: |
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16 | |
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17 | # hostname |
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18 | |
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19 | You should see: |
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20 | |
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21 | pc18.ws.nsrc.org |
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22 | |
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23 | If not, then configure your server with its name: e.g. for |
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24 | pc18.ws.nsrc.org, type: |
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25 | |
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26 | |
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27 | # hostname pc18.ws.nsrc.org |
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28 | |
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29 | Remember to replace "grpXX" with the the proper group number! |
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30 | |
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31 | Edit the file /etc/hostname (using "vi" or "joe", i.e.: editor /etc/rc.conf), |
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32 | and update the "hostname": |
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33 | |
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34 | pc18.ws.nsrc.org |
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35 | |
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36 | In the file /etc/hosts, you should add a line: |
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37 | |
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38 | 10.10.X.18 pc18.ws.nsrc.org pc18 |
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39 | |
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40 | |
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41 | Exercise |
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42 | -------- |
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43 | |
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44 | * Choose a new domain, write it down somewhere |
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45 | |
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46 | i.e.: "MYNAME.ws.nsrc.org" or "KANGURU.ws.nsrc.org" - whatever you feel |
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47 | like. |
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48 | |
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49 | (Do *NOT* choose any of the PC names, e.g. `pc18.ws.nsrc.org`, |
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50 | as your subdomain) |
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51 | |
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52 | This could for example be the name of your country code, country name, |
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53 | company name, etc... but REMEMBER that someone might pick the same name! |
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54 | First come, first serve - and it must be a subdomain of ".ws.nsrc.org". |
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55 | |
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56 | * Find someone who will agree to be slave for your domain. Please find |
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57 | someone on a different table than you (Remember RFC2182: secondaries must |
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58 | be on remote networks but here we work on a flat net). You can |
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59 | have more than one slave if you wish. |
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60 | |
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61 | * If required, installed bind9: |
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62 | |
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63 | Ubuntu: apt-get install bind9 |
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64 | |
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65 | * Create your zone file in `/etc/bind/db.MYNAME.ws.nsrc.org` |
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66 | (where MYNAME is your chosen domain) -- you can pretty much |
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67 | "copy and paste" the section below -- but remember to update |
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68 | the XXX with your IP: |
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69 | |
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70 | *** Remember, you will need to become root to create this file, |
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71 | *** so, e.g. |
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72 | *** |
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73 | *** $ cd /etc/bind/ |
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74 | *** $ sudo vi db.MYNAME.ws.nsrc.org |
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75 | *** |
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76 | *** (feel free to use another editor instead of vi, e.g. joe, ee) |
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77 | |
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78 | - - - - - - - - - - - - - cut below - - - - - - - - - - - - |
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79 | |
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80 | $TTL 10m |
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81 | @ IN SOA pcXX.ws.nsrc.org. sysadm@pcXX.ws.nsrc.org. ( |
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82 | 2011112301 ; Serial |
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83 | 10m ; Refresh |
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84 | 5m ; Retry |
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85 | 4w ; Expire |
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86 | 10m ) ; Negative |
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87 | |
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88 | IN NS pcXX.ws.nsrc.org. ; master |
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89 | IN NS pxYY.ws.nsrc.org. ; slave |
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90 | |
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91 | www IN A 10.10.0.XX ; your own IP |
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92 | |
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93 | - - - - - - - - - - - - - cut above - - - - - - - - - - - - |
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94 | |
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95 | You can replace `sysadm@pcXX.ws.nsrc.org..` with your home E-mail address |
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96 | if you want. |
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97 | |
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98 | XX and YY are the IP of your PC and your slave's. |
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99 | |
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100 | We have chosen purposely low values for TTL, refresh, and retry to make |
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101 | it easier to fix problems in the classroom. For a production domain you |
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102 | might use higher values. |
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103 | |
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104 | * Edit `/etc/bind/named.conf.options` |
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105 | |
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106 | *** Remember, you will need to become root to edit this file, |
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107 | *** so, e.g. |
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108 | *** |
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109 | *** $ cd /etc/bind |
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110 | *** $ sudo vi named.conf.options |
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111 | *** |
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112 | |
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113 | ... add another line in the options section, so it becomes: |
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114 | |
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115 | |
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116 | listen-on-v6 { any; }; |
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117 | |
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118 | allow-query { any; }; // <- this is a new line! |
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119 | |
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120 | ... so that your nameserver will now answer queries from the network |
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121 | |
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122 | Save & quit the editor. |
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123 | |
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124 | * Edit `/etc/bind/named.conf.local` and do the following: |
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125 | |
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126 | - Add a section to configure your machine as master for |
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127 | your domain, by adding something like this at the end |
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128 | (the bottom) of the file: |
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129 | |
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130 | zone "MYNAME.ws.nsrc.org" { |
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131 | type master; |
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132 | file "/etc/bind/db.MYNAME.ws.nsrc.org"; |
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133 | }; |
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134 | |
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135 | Pay attention to the ';' and '}' ! |
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136 | |
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137 | * Check that your config file and zone file are valid: |
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138 | |
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139 | $ named-checkconf |
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140 | $ named-checkzone MYNAME.ws.nsrc.org /etc/bind/db.MYNAME.ws.nsrc.org |
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141 | |
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142 | * If there are any errors, correct them ! * |
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143 | |
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144 | * Restart named (the BIND nameserver): |
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145 | |
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146 | $ sudo service bind9 restart |
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147 | |
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148 | Check the result with |
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149 | |
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150 | $ tail /var/log/messages |
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151 | |
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152 | Verify with dig that MYNAME.ws.nsrc.org. is now configured on your host: |
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153 | |
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154 | $ dig @localhost MYNAME.ws.nsrc.org. NS |
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155 | |
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156 | You can also check the nameserver status using rndc: |
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157 | |
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158 | $ sudo rndc status |
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159 | |
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160 | - If there are any errors, correct them. Some configuration errors can |
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161 | cause the daemon to die completely, in which case you may have to |
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162 | start it again: |
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163 | |
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164 | $ sudo service bind9 restart |
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165 | |
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166 | * Assist your slaves to configure themselves as slave for your domain, and |
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167 | configure yourself as a slave if asked to do so by another table. |
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168 | |
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169 | The instructions for how to do this are on the slides, but here's a hint |
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170 | on what to put in /etc/bind/named.conf.local |
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171 | |
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172 | zone "MYNAME.ws.nsrc.org" { |
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173 | type slave; |
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174 | masters { 10.10.0.XX; }; |
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175 | file "/var/cache/bind/db.MYNAME.ws.nsrc.org"; |
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176 | }; |
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177 | |
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178 | ... where XX is the IP of the MASTER PC for the zone. |
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179 | |
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180 | Remember, you will also need to be a slave for someone else's zone! |
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181 | |
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182 | When you have changed your `named.conf.local` so that you are a slave for |
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183 | someone else, make sure there are no errors in `/var/log/messages` after |
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184 | you restart your nameserver. |
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185 | |
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186 | * Check that you and your slaves are giving authoritative answers for |
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187 | your domain: |
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188 | |
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189 | # dig +norec @10.10.0.XX MYNAME.ws.nsrc.org. SOA |
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190 | # dig +norec @10.10.0.YY MYNAME.ws.nsrc.org. SOA |
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191 | |
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192 | Check that you get an AA (authoritative answer) from both, and that |
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193 | the serial numbers match. |
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194 | |
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195 | * Now you are ready to request delegation – indicate to the instructor, |
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196 | on a piece of paper: |
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197 | |
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198 | |
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199 | Domain name: ___________________ |
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200 | |
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201 | Master nameserver: pcX.ws.nsrc.org |
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202 | |
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203 | Slave nameserver: pcY.ws.nsrc.org |
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204 | |
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205 | |
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206 | * You will not get delegation until the instructor has checked: |
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207 | |
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208 | - Your nameservers are all authoritative for your domain |
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209 | - They all have the same SOA serial number |
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210 | - The NS records within the zone match the list of servers you are |
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211 | requesting delegation for |
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212 | - The slave(s) are not on the same side of the room as you :) |
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213 | |
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214 | => This is called policy! |
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215 | |
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216 | * Once you have delegation, try to resolve www.MYNAME.ws.nsrc.org |
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217 | |
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218 | - On your own machine |
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219 | - On someone else's machine (who is not slave for you): |
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220 | |
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221 | # dig @10.10.0.XX www.MYNAME.ws.nsrc.org (where MYNAME is your domain) |
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222 | |
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223 | * Add a new resource record to your zone file. Remember to update the |
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224 | serial number. Check that your slaves have updated. Try resolving this |
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225 | new name. |
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