]> git.piffa.net Git - doc/.git/blobdiff - servizi.html
Modificato servizi per DNSMASQ
[doc/.git] / servizi.html
index 8facfa0e4e5dfcadae688ae026cc6e3f70f886c0..f0fc4e05c95f28d84c1fc53b668273d38ebc1ae7 100644 (file)
           <tr class="field">
             <th class="field-name">Version:</th>
 
-            <td class="field-body">0.5</td>
+            <td class="field-body">0.6</td>
           </tr>
         </tbody>
       </table>
 
             <li><a class="reference internal" href="#dig" id="id52"
             name="id52">4.5&nbsp;&nbsp;&nbsp;Dig</a></li>
+
+            <li><a class="reference internal" href="#resolv-conf"
+            id="id53" name=
+            "id53">4.6&nbsp;&nbsp;&nbsp;resolv.conf</a></li>
+
+            <li><a class="reference internal" href="#etc-hosts" id=
+            "id54" name=
+            "id54">4.7&nbsp;&nbsp;&nbsp;/etc/hosts</a></li>
+
+            <li><a class="reference internal" href="#hostname" id=
+            "id55" name=
+            "id55">4.8&nbsp;&nbsp;&nbsp;Hostname</a></li>
           </ul>
         </li>
 
-        <li><a class="reference internal" href="#dnsmasq" id="id53"
-        name="id53">5&nbsp;&nbsp;&nbsp;DNSmasq</a></li>
+        <li>
+          <a class="reference internal" href="#dnsmasq" id="id56"
+          name="id56">5&nbsp;&nbsp;&nbsp;DNSmasq</a>
+
+          <ul class="auto-toc">
+            <li><a class="reference internal" href=
+            "#configurazione" id="id57" name=
+            "id57">5.1&nbsp;&nbsp;&nbsp;Configurazione</a></li>
+
+            <li><a class="reference internal" href="#dhcp" id=
+            "id58" name="id58">5.2&nbsp;&nbsp;&nbsp;DHCP</a></li>
+
+            <li><a class="reference internal" href="#dns-cache" id=
+            "id59" name="id59">5.3&nbsp;&nbsp;&nbsp;DNS
+            cache</a></li>
+
+            <li><a class="reference internal" href="#dhcpd" id=
+            "id60" name="id60">5.4&nbsp;&nbsp;&nbsp;DHCPd</a></li>
+          </ul>
+        </li>
 
         <li>
-          <a class="reference internal" href="#samba" id="id54"
-          name="id54">6&nbsp;&nbsp;&nbsp;Samba</a>
+          <a class="reference internal" href="#samba" id="id61"
+          name="id61">6&nbsp;&nbsp;&nbsp;Samba</a>
 
           <ul class="auto-toc">
             <li><a class="reference internal" href="#pacchetti" id=
-            "id55" name=
-            "id55">6.1&nbsp;&nbsp;&nbsp;Pacchetti</a></li>
+            "id62" name=
+            "id62">6.1&nbsp;&nbsp;&nbsp;Pacchetti</a></li>
 
             <li><a class="reference internal" href=
-            "#passwords-e-autenticazione" id="id56" name=
-            "id56">6.2&nbsp;&nbsp;&nbsp;Passwords e
+            "#passwords-e-autenticazione" id="id63" name=
+            "id63">6.2&nbsp;&nbsp;&nbsp;Passwords e
             autenticazione</a></li>
 
             <li><a class="reference internal" href=
-            "#creazione-utenti" id="id57" name=
-            "id57">6.3&nbsp;&nbsp;&nbsp;Creazione Utenti</a></li>
+            "#creazione-utenti" id="id64" name=
+            "id64">6.3&nbsp;&nbsp;&nbsp;Creazione Utenti</a></li>
 
             <li>
               <a class="reference internal" href=
-              "#creare-la-condivisione" id="id58" name=
-              "id58">6.4&nbsp;&nbsp;&nbsp;Creare la
+              "#creare-la-condivisione" id="id65" name=
+              "id65">6.4&nbsp;&nbsp;&nbsp;Creare la
               condivisione</a>
 
               <ul class="auto-toc">
                 <li><a class="reference internal" href=
                 "#sicurezza-permessi-di-esecuzione-sul-server" id=
-                "id59" name=
-                "id59">6.4.1&nbsp;&nbsp;&nbsp;Sicurezza: permessi
+                "id66" name=
+                "id66">6.4.1&nbsp;&nbsp;&nbsp;Sicurezza: permessi
                 di esecuzione sul server</a></li>
               </ul>
             </li>
 
             <li><a class="reference internal" href=
             "#configurazione-dell-applicativo-samba-vero-e-proprio"
-            id="id60" name=
-            "id60">6.5&nbsp;&nbsp;&nbsp;Configurazione
+            id="id67" name=
+            "id67">6.5&nbsp;&nbsp;&nbsp;Configurazione
             dell'applicativo Samba vero e proprio.</a></li>
 
             <li><a class="reference internal" href=
-            "#testare-il-servizio" id="id61" name=
-            "id61">6.6&nbsp;&nbsp;&nbsp;Testare il
+            "#testare-il-servizio" id="id68" name=
+            "id68">6.6&nbsp;&nbsp;&nbsp;Testare il
             Servizio</a></li>
           </ul>
         </li>
 
         <li>
-          <a class="reference internal" href="#firewall" id="id62"
-          name="id62">7&nbsp;&nbsp;&nbsp;Firewall</a>
+          <a class="reference internal" href="#firewall" id="id69"
+          name="id69">7&nbsp;&nbsp;&nbsp;Firewall</a>
 
           <ul class="auto-toc">
             <li><a class="reference internal" href="#links" id=
-            "id63" name="id63">7.1&nbsp;&nbsp;&nbsp;Links</a></li>
+            "id70" name="id70">7.1&nbsp;&nbsp;&nbsp;Links</a></li>
 
             <li><a class="reference internal" href="#ipfilter" id=
-            "id64" name=
-            "id64">7.2&nbsp;&nbsp;&nbsp;Ipfilter</a></li>
+            "id71" name=
+            "id71">7.2&nbsp;&nbsp;&nbsp;Ipfilter</a></li>
 
             <li>
               <a class="reference internal" href=
-              "#progettazione-di-un-firewall" id="id65" name=
-              "id65">7.3&nbsp;&nbsp;&nbsp;Progettazione di un
+              "#progettazione-di-un-firewall" id="id72" name=
+              "id72">7.3&nbsp;&nbsp;&nbsp;Progettazione di un
               firewall</a>
 
               <ul class="auto-toc">
                 <li><a class="reference internal" href=
-                "#collocazione" id="id66" name=
-                "id66">7.3.1&nbsp;&nbsp;&nbsp;Collocazione</a></li>
+                "#collocazione" id="id73" name=
+                "id73">7.3.1&nbsp;&nbsp;&nbsp;Collocazione</a></li>
 
                 <li><a class="reference internal" href=
-                "#policy-di-default" id="id67" name=
-                "id67">7.3.2&nbsp;&nbsp;&nbsp;Policy di
+                "#policy-di-default" id="id74" name=
+                "id74">7.3.2&nbsp;&nbsp;&nbsp;Policy di
                 default</a></li>
 
                 <li><a class="reference internal" href="#hardware"
-                id="id68" name=
-                "id68">7.3.3&nbsp;&nbsp;&nbsp;Hardware</a></li>
+                id="id75" name=
+                "id75">7.3.3&nbsp;&nbsp;&nbsp;Hardware</a></li>
               </ul>
             </li>
 
             <li><a class="reference internal" href=
             "#percorso-dei-pacchetti-tra-tabelle-e-catene" id=
-            "id69" name="id69">7.4&nbsp;&nbsp;&nbsp;Percorso dei
+            "id76" name="id76">7.4&nbsp;&nbsp;&nbsp;Percorso dei
             pacchetti tra tabelle e catene</a></li>
 
             <li>
               <a class="reference internal" href=
-              "#concetti-di-base" id="id70" name=
-              "id70">7.5&nbsp;&nbsp;&nbsp;Concetti di base</a>
+              "#concetti-di-base" id="id77" name=
+              "id77">7.5&nbsp;&nbsp;&nbsp;Concetti di base</a>
 
               <ul class="auto-toc">
                 <li><a class="reference internal" href=
-                "#tabelle-catene-regole" id="id71" name=
-                "id71">7.5.1&nbsp;&nbsp;&nbsp;Tabelle, catene,
+                "#tabelle-catene-regole" id="id78" name=
+                "id78">7.5.1&nbsp;&nbsp;&nbsp;Tabelle, catene,
                 regole</a></li>
 
                 <li><a class="reference internal" href="#match" id=
-                "id72" name=
-                "id72">7.5.2&nbsp;&nbsp;&nbsp;Match</a></li>
+                "id79" name=
+                "id79">7.5.2&nbsp;&nbsp;&nbsp;Match</a></li>
 
                 <li><a class="reference internal" href="#targets"
-                id="id73" name=
-                "id73">7.5.3&nbsp;&nbsp;&nbsp;Targets</a></li>
+                id="id80" name=
+                "id80">7.5.3&nbsp;&nbsp;&nbsp;Targets</a></li>
               </ul>
             </li>
 
             <li><a class="reference internal" href=
-            "#tabella-filter" id="id74" name=
-            "id74">7.6&nbsp;&nbsp;&nbsp;Tabella Filter</a></li>
+            "#tabella-filter" id="id81" name=
+            "id81">7.6&nbsp;&nbsp;&nbsp;Tabella Filter</a></li>
 
             <li><a class="reference internal" href=
-            "#flush-automatico-per-macchine-remote" id="id75" name=
-            "id75">7.7&nbsp;&nbsp;&nbsp;Flush automatico per
+            "#flush-automatico-per-macchine-remote" id="id82" name=
+            "id82">7.7&nbsp;&nbsp;&nbsp;Flush automatico per
             macchine remote</a></li>
 
             <li><a class="reference internal" href=
-            "#gestione-regole-rules" id="id76" name=
-            "id76">7.8&nbsp;&nbsp;&nbsp;Gestione regole
+            "#gestione-regole-rules" id="id83" name=
+            "id83">7.8&nbsp;&nbsp;&nbsp;Gestione regole
             (rules)</a></li>
           </ul>
         </li>
 
-        <li><a class="reference internal" href="#note" id="id77"
-        name="id77">8&nbsp;&nbsp;&nbsp;NOTE</a></li>
+        <li><a class="reference internal" href="#note" id="id84"
+        name="id84">8&nbsp;&nbsp;&nbsp;NOTE</a></li>
       </ul>
     </div>
 
@@ -2616,12 +2646,145 @@ l.google.com.           80856   IN      NS      g.l.google.com.
 
           <p>...</p>
         </blockquote>
+
+        <dl class="docutils">
+          <dt>dig @nome_dns</dt>
+
+          <dd>Permette di fare una query ad un server dns
+          particolare. Es: <tt class=
+          "docutils literal"><span class="pre">dig</span>
+          <span class="pre">@151.99.25.1</span> <span class=
+          "pre">www.google.it</span></tt></dd>
+
+          <dt>dig MX www.google.it</dt>
+
+          <dd>Chiede un campo in particolare, in questo caso il
+          campo MX</dd>
+
+          <dt>dig ANY www.google.it</dt>
+
+          <dd>Chiede tutti i campi, non solo i campi
+          <em>a</em></dd>
+
+          <dt>dig -x 74.125.43.104</dt>
+
+          <dd>Effettua una richiesta inversa: dall'ip al PTR
+          associato.</dd>
+        </dl>
+      </div>
+
+      <div class="section" id="resolv-conf">
+        <h2><a class="toc-backref" href=
+        "#id53">4.6&nbsp;&nbsp;&nbsp;resolv.conf</a></h2>
+
+        <p>Il file <tt class="docutils literal"><span class=
+        "pre">/etc/resolv.conf</span></tt> contiene le impostazioni
+        sul dns usato dal sistema, in genere anche altre
+        applicazioni che devono effettuare query DNS leggono
+        resolv.conf per conoscere l'ubicazione del DNS.</p>
+
+        <p>/etc/resolv.conf:</p>
+        <pre class="literal-block">
+- ``nameserver``: indica il nameserver da utilizzare, indicato con l'indirizzo ip.
+
+- ``domain``: indica il nome di dominio della rete attuale, vedi voce sucessiva.
+
+- ``search``: nome di dominio usato dalla rete sul quale cercare gli hosts. Ad esempio se impostato su ``piffa.net`` pingando l'host ``bender`` viene automaticamente fatto un tentativo di ricerca per ``bender.piffa.net``.
+</pre>
+
+        <p>Si veda anche la pagina man di resolv.conf.</p>
+
+        <p>Attenzione: se si usa un client DHCP o simile questo
+        file potra' essere riscritto automaticamente in base a
+        quanto ottenuto dal DHCP. Si veda la documentazione del
+        pacchtto <tt class="docutils literal"><span class=
+        "pre">resolvconf</span></tt>.</p>
+      </div>
+
+      <div class="section" id="etc-hosts">
+        <h2><a class="toc-backref" href=
+        "#id54">4.7&nbsp;&nbsp;&nbsp;/etc/hosts</a></h2>
+
+        <p>Tabella statica per l'associazione tra IP e nomi di
+        dominio:</p>
+        <pre class="literal-block">
+# cat /etc/hosts
+</pre>
+
+        <blockquote>
+          127.0.0.1 localhost.localdomain localhost 10.10.208.162
+          daniela daniela.piffa.net 10.10.208.254 mirror
+          mirror.piffa.net 91.191.138.15 thepiratebay.org
+          192.168.0.11 chrome chrome.mydomain.com
+        </blockquote>
+
+        <p>Il contenuto e' un associazione tra un <em>IP</em> e
+        stringhe di testo (anche piu' di una es: <tt class=
+        "docutils literal"><span class="pre">mirror</span></tt> e
+        <tt class="docutils literal"><span class=
+        "pre">mirror.piffa.net</span></tt>), un record per
+        riga.</p>
+
+        <p>Il problema e' la gestione di questo file: quando gli
+        host cambiano IP si devono aggiornare i records, e c'e' poi
+        il problema di distribuire questo file tra i vari hosts
+        della propia LAN. Un metodo semplice per distribuire questo
+        file e' utilizzare <tt class=
+        "docutils literal"><span class="pre">Dnsmasq</span></tt>:
+        questo infatti legge e onora il file <tt class=
+        "docutils literal"><span class="pre">hosts</span></tt>
+        locale e lo <em>distribuisce</em> ai clients.</p>
+
+        <p>Modificare (riconducendola a un ip interno, cosi'
+        annullandola) la risoluzione di un nome di dominio e' un
+        modo drastico e funzionale per <em>annullarlo</em>
+        rendendolo indisponibile alla propia rete locale, ad
+        esempio aggiungere al file <tt class=
+        "docutils literal"><span class=
+        "pre">/etc/hosts</span></tt>:</p>
+        <pre class="literal-block">
+127.0.0.1       www.facebook.com
+</pre>
+
+        <p>Impedira' agli utenti della LAN di raggiungere
+        <em>facebook</em>, ora reindirizzato a i``localhost``.</p>
+      </div>
+
+      <div class="section" id="hostname">
+        <h2><a class="toc-backref" href=
+        "#id55">4.8&nbsp;&nbsp;&nbsp;Hostname</a></h2>
+
+        <p>Ogni computer ha un <em>propio nome</em> visualizzabile
+        (e modificabile) con il comando <tt class=
+        "docutils literal"><span class=
+        "pre">hostname</span></tt>.</p>
+
+        <p>Per modificare in modo permanente il nome del computer
+        si modifichi il contenuto del file <tt class=
+        "docutils literal"><span class=
+        "pre">/etc/hostname</span></tt>.</p>
+
+        <p>Tipicamente si vuole mantenere una correlazione tra il
+        nome dell'host, o meglio la stringa con cui il server si
+        qualifica all'esterno, e il <em>PTR</em> dell'ip. Nel caso
+        di <em>servizi virtuali</em> ci sara' un <em>nome
+        server</em> principale associato al <em>PTR</em> condiviso.
+        Non e' automatico che un servizio, ad esempio un server di
+        posta, si qualifichi leggendo il contenuto di questo file e
+        magari aggiungendo come suffisso il dominio di cui fa parte
+        l'host: a volte questo parametro puo' essere specificato
+        nel file di configurazione del servizio:</p>
+        <pre class="literal-block">
+* Squid: ``visible_hostname``
+
+* Postfix: ``myhostname``
+</pre>
       </div>
     </div>
 
     <div class="section" id="dnsmasq">
       <h1><a class="toc-backref" href=
-      "#id53">5&nbsp;&nbsp;&nbsp;DNSmasq</a></h1>
+      "#id56">5&nbsp;&nbsp;&nbsp;DNSmasq</a></h1>
 
       <p>Dnsmasq puo' svolgere le funzioni di un DNS cache /
       forwarder e un server DHCP caratterizzato dalla facilita' di
@@ -2656,11 +2819,136 @@ l.google.com.           80856   IN      NS      g.l.google.com.
       Molto utile per scopi didattici, sopratutto per testare
       server SMTP impostando al volo i campi MX per nomi di dominio
       fittizi.</p>
+
+      <div class="section" id="configurazione">
+        <h2><a class="toc-backref" href=
+        "#id57">5.1&nbsp;&nbsp;&nbsp;Configurazione</a></h2>
+
+        <p>Vediamo alcune direttive di basi del file di
+        configurazione <tt class="docutils literal"><span class=
+        "pre">/etc/dnsmasq.conf</span></tt> utili per la
+        configurazione sia del DNS cache che per il DHCP
+        server:</p>
+
+        <dl class="docutils">
+          <dt>domain-needed</dt>
+
+          <dd>Non inoltrare query ai server DNS esterni per nomi
+          semplici (es andrea, portatile, pippo) che verranno
+          risolti solo in locale o causeranno direttamente una
+          risposta <em>not found</em> .</dd>
+
+          <dt>bogus-priv</dt>
+
+          <dd>Simile alla voce precedente ma per i reverse
+          look-up.</dd>
+
+          <dt>domain</dt>
+
+          <dd>Nome di dominio della rete da passare ai client.</dd>
+
+          <dt>expand_hosts</dt>
+
+          <dd>Aggiunge il <tt class="docutils literal"><span class=
+          "pre">nome</span> <span class="pre">host</span></tt> (
+          <tt class="docutils literal"><span class=
+          "pre">/etc/hostname</span></tt>) dei client al nome di
+          dominio per qualificarli in rete, senza bisogno di dover
+          comporre a un elenco statico di record nel file
+          <tt class="docutils literal"><span class=
+          "pre">/etc/hosts</span></tt> o nello stesso file di
+          configurazione di dnsmasq. Es: se un vostro client si
+          chiama <tt class="docutils literal"><span class=
+          "pre">chrome</span></tt> e il vostro dominio <tt class=
+          "docutils literal"><span class=
+          "pre">piffa.net</span></tt> dnsmasq rendera' disponibile
+          il campo <em>A</em> per il dominio <tt class=
+          "docutils literal"><span class=
+          "pre">chrome.piffa.net</span></tt> diretto all'ip che
+          verra' assegnato al client.</dd>
+        </dl>
+      </div>
+
+      <div class="section" id="dhcp">
+        <h2><a class="toc-backref" href=
+        "#id58">5.2&nbsp;&nbsp;&nbsp;DHCP</a></h2>
+
+        <p>Per attivare il demone DHCP di dnsmaq basta aggiungere
+        al file di configurazione il <em>range</em> degli ip che si
+        vuole assegnare ai client con il <em>lease time</em> (tempo
+        di rilascio: quanto a lungo saranno validi gli ip
+        assegnati) espresso in ore.</p>
+
+        <p>Si faccia <em>attenzione</em>: in una rete puo' esseere
+        presente <strong>un solo server DHCP</strong>, o per meglio
+        dire qualunque server DHCP ascolta sul broadcast <tt class=
+        "docutils literal"><span class=
+        "pre">255.255.255.255</span></tt> e potrebbe rispondere a
+        un pacchetto di richesta DHCP. Quindi non fate partire
+        inavvertitamente un server DHCP in una rete gia' servita e
+        <strong>non vi azzardate ad andare in giro con un portatile
+        con un server DHCP attivo</strong> nelle reti altrui.
+        Questo vale anche per i laboratori di informatica dei corsi
+        di reti: non fate partire il vostro server DHCP se siete
+        collegati alla rete interna!</p>
+
+        <p>/etc/dnsmasq.conf (riga 118):</p>
+        <pre class="literal-block">
+dhcp-range=192.168.0.20,192.168.0.50,24h
+</pre>
+      </div>
+
+      <div class="section" id="dns-cache">
+        <h2><a class="toc-backref" href=
+        "#id59">5.3&nbsp;&nbsp;&nbsp;DNS cache</a></h2>
+
+        <p>Aggiungere al file <tt class=
+        "docutils literal"><span class=
+        "pre">/etc/resolv.conif</span></tt> il nameserver localhost
+        in cima alla lista dei <em>nameserver</em> disponibili.
+        Dnsmasq usera' la propia cache e in caso non abbia
+        disponibile il <em>record DNS</em> richiesto fara' partire
+        una query al primo DNS:</p>
+        <pre class="literal-block">
+nameserver      127.0.0.1
+</pre>
+
+        <p>Questo pero' potrebbe essere problematico se un altro
+        servizio, ad esempio il DHCP client, riscrive il contenuto
+        del file <tt class="docutils literal"><span class=
+        "pre">/etc/resolv.conf</span></tt>. Per superare il
+        problema si aggiunga (riga 20) al file di configurazione
+        <tt class="docutils literal"><span class=
+        "pre">/etc/dhcp3/dhclient.conf</span></tt></p>
+        <pre class="literal-block">
+prepend domain-name-servers 127.0.0.1;
+</pre>
+
+        <p>Oppure potrebbe essere il nostro <em>PPP client</em>
+        (per la connessione ADSL) a intervenire sul file <tt class=
+        "docutils literal"><span class=
+        "pre">//etc/resolv.conf</span></tt>, si modifichi quindi
+        <tt class="docutils literal"><span class=
+        "pre">/etc/ppp/peers/dsl-provider</span></tt> commentando
+        <tt class="docutils literal"><span class=
+        "pre">usepeerdns</span></tt>. Se la vostra connessione ad
+        internet e' ADSL raramente dovreste aver bisogno di
+        cambiare i DNS una volta impostati (a meno che non usiate
+        un portatile!).</p>
+      </div>
+
+      <div class="section" id="dhcpd">
+        <h2><a class="toc-backref" href=
+        "#id60">5.4&nbsp;&nbsp;&nbsp;DHCPd</a></h2>
+
+        <p>Dnsmasq puo' lavorare anche come DHCP server per la
+        vostra LAN.</p>
+      </div>
     </div>
 
     <div class="section" id="samba">
       <h1><a class="toc-backref" href=
-      "#id54">6&nbsp;&nbsp;&nbsp;Samba</a></h1>
+      "#id61">6&nbsp;&nbsp;&nbsp;Samba</a></h1>
 
       <p>Samba e' un progetto libero che fornisce servizi di
       condivisione di file e stampanti a client SMB/CIFS.</p>
@@ -2681,7 +2969,7 @@ l.google.com.           80856   IN      NS      g.l.google.com.
 
       <div class="section" id="pacchetti">
         <h2><a class="toc-backref" href=
-        "#id55">6.1&nbsp;&nbsp;&nbsp;Pacchetti</a></h2>
+        "#id62">6.1&nbsp;&nbsp;&nbsp;Pacchetti</a></h2>
 
         <p>Pacchetti da installare per utilizzare Samba in
         modalita' client <a class="footnote-reference" href="#id5"
@@ -2734,7 +3022,7 @@ dpkg-reconfigure samba-common
 
       <div class="section" id="passwords-e-autenticazione">
         <h2><a class="toc-backref" href=
-        "#id56">6.2&nbsp;&nbsp;&nbsp;Passwords e
+        "#id63">6.2&nbsp;&nbsp;&nbsp;Passwords e
         autenticazione</a></h2>
 
         <p>Per poter configurare Samba in modo che usi un sistema
@@ -2795,7 +3083,7 @@ dpkg-reconfigure samba-common
 
       <div class="section" id="creazione-utenti">
         <h2><a class="toc-backref" href=
-        "#id57">6.3&nbsp;&nbsp;&nbsp;Creazione Utenti</a></h2>
+        "#id64">6.3&nbsp;&nbsp;&nbsp;Creazione Utenti</a></h2>
 
         <p>Creiamo per primo l'utente sotto GNU/Linux, facendo
         attenzione a <em>non dargli una shell di sistema</em>. Gli
@@ -2832,7 +3120,7 @@ smbpasswd  sambo
 
       <div class="section" id="creare-la-condivisione">
         <h2><a class="toc-backref" href=
-        "#id58">6.4&nbsp;&nbsp;&nbsp;Creare la
+        "#id65">6.4&nbsp;&nbsp;&nbsp;Creare la
         condivisione</a></h2>
 
         <p>La condivisione altro non e' che una cartella sul server
@@ -2859,7 +3147,7 @@ smbpasswd  sambo
         <div class="section" id=
         "sicurezza-permessi-di-esecuzione-sul-server">
           <h3><a class="toc-backref" href=
-          "#id59">6.4.1&nbsp;&nbsp;&nbsp;Sicurezza: permessi di
+          "#id66">6.4.1&nbsp;&nbsp;&nbsp;Sicurezza: permessi di
           esecuzione sul server</a></h3>
 
           <p>Bisognerebbe notare sul server i permessi di
@@ -2889,7 +3177,7 @@ smbpasswd  sambo
       <div class="section" id=
       "configurazione-dell-applicativo-samba-vero-e-proprio">
         <h2><a class="toc-backref" href=
-        "#id60">6.5&nbsp;&nbsp;&nbsp;Configurazione
+        "#id67">6.5&nbsp;&nbsp;&nbsp;Configurazione
         dell'applicativo Samba vero e proprio.</a></h2>
 
         <p>Avendo preparato gli utenti (ancora una volta: non si
@@ -2929,7 +3217,7 @@ smbpasswd  sambo
 
       <div class="section" id="testare-il-servizio">
         <h2><a class="toc-backref" href=
-        "#id61">6.6&nbsp;&nbsp;&nbsp;Testare il Servizio</a></h2>
+        "#id68">6.6&nbsp;&nbsp;&nbsp;Testare il Servizio</a></h2>
 
         <p>Come testare il servizio</p>
 
@@ -2969,7 +3257,7 @@ mount -t smbfs //localhost/sambo_share /mnt/sambo_mount/ --verbose -o user=sambo
 
     <div class="section" id="firewall">
       <h1><a class="toc-backref" href=
-      "#id62">7&nbsp;&nbsp;&nbsp;Firewall</a></h1>
+      "#id69">7&nbsp;&nbsp;&nbsp;Firewall</a></h1>
 
       <p>In Informatica, nell'ambito delle reti di computer, un
       firewall (termine inglese dal significato originario di
@@ -3019,7 +3307,7 @@ mount -t smbfs //localhost/sambo_share /mnt/sambo_mount/ --verbose -o user=sambo
 
       <div class="section" id="links">
         <h2><a class="toc-backref" href=
-        "#id63">7.1&nbsp;&nbsp;&nbsp;Links</a></h2>
+        "#id70">7.1&nbsp;&nbsp;&nbsp;Links</a></h2>
 
         <ul class="simple">
           <li><a class="reference external" href=
@@ -3033,7 +3321,7 @@ mount -t smbfs //localhost/sambo_share /mnt/sambo_mount/ --verbose -o user=sambo
 
       <div class="section" id="ipfilter">
         <h2><a class="toc-backref" href=
-        "#id64">7.2&nbsp;&nbsp;&nbsp;Ipfilter</a></h2>
+        "#id71">7.2&nbsp;&nbsp;&nbsp;Ipfilter</a></h2>
 
         <p>Link: <a class="reference external" href=
         "http://iptables-tutorial.frozentux.net/iptables-tutorial.html#IPFILTERING">
@@ -3069,7 +3357,7 @@ mount -t smbfs //localhost/sambo_share /mnt/sambo_mount/ --verbose -o user=sambo
 
       <div class="section" id="progettazione-di-un-firewall">
         <h2><a class="toc-backref" href=
-        "#id65">7.3&nbsp;&nbsp;&nbsp;Progettazione di un
+        "#id72">7.3&nbsp;&nbsp;&nbsp;Progettazione di un
         firewall</a></h2>
 
         <p>Per implementare un firewall bisogna decidere un aio di
@@ -3078,7 +3366,7 @@ mount -t smbfs //localhost/sambo_share /mnt/sambo_mount/ --verbose -o user=sambo
 
         <div class="section" id="collocazione">
           <h3><a class="toc-backref" href=
-          "#id66">7.3.1&nbsp;&nbsp;&nbsp;Collocazione</a></h3>
+          "#id73">7.3.1&nbsp;&nbsp;&nbsp;Collocazione</a></h3>
 
           <p>DMZ e MZ, internet, intranet, extranet. Frammentazione
           della rete, decidere se diversi reparti di una azienda si
@@ -3110,7 +3398,7 @@ mount -t smbfs //localhost/sambo_share /mnt/sambo_mount/ --verbose -o user=sambo
 
         <div class="section" id="policy-di-default">
           <h3><a class="toc-backref" href=
-          "#id67">7.3.2&nbsp;&nbsp;&nbsp;Policy di default</a></h3>
+          "#id74">7.3.2&nbsp;&nbsp;&nbsp;Policy di default</a></h3>
 
           <p>Drop o Accept: conseguenze per sicurezza, facilita' di
           gestione.</p>
@@ -3118,7 +3406,7 @@ mount -t smbfs //localhost/sambo_share /mnt/sambo_mount/ --verbose -o user=sambo
 
         <div class="section" id="hardware">
           <h3><a class="toc-backref" href=
-          "#id68">7.3.3&nbsp;&nbsp;&nbsp;Hardware</a></h3>
+          "#id75">7.3.3&nbsp;&nbsp;&nbsp;Hardware</a></h3>
 
           <p>Sostanzialmente potremmo distinquere due tipologie di
           hardware:</p>
@@ -3146,7 +3434,7 @@ mount -t smbfs //localhost/sambo_share /mnt/sambo_mount/ --verbose -o user=sambo
       <div class="section" id=
       "percorso-dei-pacchetti-tra-tabelle-e-catene">
         <h2><a class="toc-backref" href=
-        "#id69">7.4&nbsp;&nbsp;&nbsp;Percorso dei pacchetti tra
+        "#id76">7.4&nbsp;&nbsp;&nbsp;Percorso dei pacchetti tra
         tabelle e catene</a></h2>
 
         <p>link: <a class="reference external" href=
@@ -3156,11 +3444,11 @@ mount -t smbfs //localhost/sambo_share /mnt/sambo_mount/ --verbose -o user=sambo
 
       <div class="section" id="concetti-di-base">
         <h2><a class="toc-backref" href=
-        "#id70">7.5&nbsp;&nbsp;&nbsp;Concetti di base</a></h2>
+        "#id77">7.5&nbsp;&nbsp;&nbsp;Concetti di base</a></h2>
 
         <div class="section" id="tabelle-catene-regole">
           <h3><a class="toc-backref" href=
-          "#id71">7.5.1&nbsp;&nbsp;&nbsp;Tabelle, catene,
+          "#id78">7.5.1&nbsp;&nbsp;&nbsp;Tabelle, catene,
           regole</a></h3>
 
           <p>Iptables lavora su 3 tabelle (tables) di default:</p>
@@ -3187,7 +3475,7 @@ mount -t smbfs //localhost/sambo_share /mnt/sambo_mount/ --verbose -o user=sambo
 
         <div class="section" id="match">
           <h3><a class="toc-backref" href=
-          "#id72">7.5.2&nbsp;&nbsp;&nbsp;Match</a></h3>
+          "#id79">7.5.2&nbsp;&nbsp;&nbsp;Match</a></h3>
 
           <p>I Match di una regola (rule) servono a testare un
           pacchetto per valutare se corrisponda a certe
@@ -3239,7 +3527,7 @@ mount -t smbfs //localhost/sambo_share /mnt/sambo_mount/ --verbose -o user=sambo
 
         <div class="section" id="targets">
           <h3><a class="toc-backref" href=
-          "#id73">7.5.3&nbsp;&nbsp;&nbsp;Targets</a></h3>
+          "#id80">7.5.3&nbsp;&nbsp;&nbsp;Targets</a></h3>
 
           <p>Se un pacchetto soddisfa le condizioni del Match
           <em>salta</em> (jump) su uno dei target possibili, in
@@ -3368,7 +3656,7 @@ mount -t smbfs //localhost/sambo_share /mnt/sambo_mount/ --verbose -o user=sambo
 
       <div class="section" id="tabella-filter">
         <h2><a class="toc-backref" href=
-        "#id74">7.6&nbsp;&nbsp;&nbsp;Tabella Filter</a></h2>
+        "#id81">7.6&nbsp;&nbsp;&nbsp;Tabella Filter</a></h2>
 
         <p>E' quella implicita e predefinita (-t filter) Riguarda
         le attivitÃ&nbsp; di filtraggio del traffico. Ha 3 catene
@@ -3392,7 +3680,7 @@ mount -t smbfs //localhost/sambo_share /mnt/sambo_mount/ --verbose -o user=sambo
       <div class="section" id=
       "flush-automatico-per-macchine-remote">
         <h2><a class="toc-backref" href=
-        "#id75">7.7&nbsp;&nbsp;&nbsp;Flush automatico per macchine
+        "#id82">7.7&nbsp;&nbsp;&nbsp;Flush automatico per macchine
         remote</a></h2>
 
         <p>Se state provando una configurazione del firewall per
@@ -3419,7 +3707,7 @@ at&gt; [CTR+d]
 
       <div class="section" id="gestione-regole-rules">
         <h2><a class="toc-backref" href=
-        "#id76">7.8&nbsp;&nbsp;&nbsp;Gestione regole
+        "#id83">7.8&nbsp;&nbsp;&nbsp;Gestione regole
         (rules)</a></h2>
 
         <p>Il comando iptables viene usato per ogni attivitÃ&nbsp;
@@ -3487,7 +3775,7 @@ at&gt; [CTR+d]
 
     <div class="section" id="note">
       <h1><a class="toc-backref" href=
-      "#id77">8&nbsp;&nbsp;&nbsp;NOTE</a></h1>
+      "#id84">8&nbsp;&nbsp;&nbsp;NOTE</a></h1>
 
       <ul class="simple">
         <li>controllare apache</li>