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Longer Socat examples are now splitted into two or three lines; improved CSS

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This commit is contained in:
Gerhard Rieger 2023-04-02 20:55:22 +02:00
parent 7cbe0b645b
commit c3719e7603
8 changed files with 774 additions and 310 deletions

22
doc/socat-tun.html
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@ -53,14 +53,20 @@ the two socat instances; the TUN interfaces both have the same quality.
<h3>TUN Server</h3>
<span class="frame"><span class="shell">socat -d -d UDP-LISTEN:11443,reuseaddr TUN:192.168.255.1/24,up</span></span>
<span class="shell">socat -d -d \
UDP-LISTEN:11443 \
TUN:192.168.255.1/24,up
</span>
<p>After starting this command, socat will wait for a connection and then
create a TUN pseudo network device with address 192.168.255.1; the bit number
specifies the mask of the network that is pretended to be connected on this
interface.</p>
<h3>TUN Client</h3>
<span class="frame"><span class="shell">socat UDP:1.2.3.4:11443 TUN:192.168.255.2/24,up</span></span>
<span class="shell">socat \
UDP:1.2.3.4:11443 \
TUN:192.168.255.2/24,up
</span>
<p>This command should establish a connection to the server and create the TUN
device on the client.</p>
@ -85,17 +91,17 @@ the <tt>ifconfig</tt> command.
<h3>Test TUN integration</h3>
<p>
If you get error messages like this:</p>
<table border="1" bgcolor="#e08080"><tr><td><tt>... E unknown device/address "tun"</tt></td></tr></table>
<span class="error">... E unknown device/address "tun"</span>
<p>your socat executable probably does not provide TUN/TAP support. Potential
reasons: you are not on Linux or are using an older version of socat.
</p>
<h3>Missing kernel support</h3>
<p>An error message like:</p>
<table border="1" bgcolor="#e08080"><tr><td><tt>... E open("/dev/net/tun", 02, 0666): No such file or directory</tt></td></tr></table>
<span class="error">... E open("/dev/net/tun", 02, 0666): No such file or directory</span>
<p>indicates that your kernel either needs to load the tun module or does not
have TUN/TAP support compiled in. Try to load the module:</p>
<span class="frame"><span class="shell">modprobe tun</span></span>
<span class="shell">modprobe tun</span>
<p>and check
for /dev/net/tun. If that does not succeed you need to
rebuild your kernel with the appropriate configuration (probably under
@ -104,14 +110,14 @@ reasons: you are not on Linux or are using an older version of socat.
<h3>TUN cloning device permissions</h3>
<p>An error message like:</p>
<table border="1" bgcolor="#e08080"><tr><td><tt>... E open("/dev/net/tun", 02, 0666): Permission denied</tt></td></tr></table>
<span class="error">... E open("/dev/net/tun", 02, 0666): Permission denied</span>
<p>indicates that you do not have permission to read or write the TUN cloning
device. Check its permission and ownership.</p>
<h3>Interface down</h3>
<p>If no error occurs but the pings do not work check if the network devices
have been created:</p>
<span class="frame"><span class="shell">ifconfig tun0</span></span>
<span class="shell">ifconfig tun0</span>
<p>The output should look like:</p>
<pre>
tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
@ -128,7 +134,7 @@ tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
<h3>Routing</h3>
<p></p>
<span class="frame"><span class="shell">netstat -an |fgrep 192.168.255</span></span>
<span class="shell">netstat -an |fgrep 192.168.255</span>
<p>The output should look like:</p>
<pre>
192.168.255.0 0.0.0.0 255.255.255.0 U 0 0 0 tun0