= I can ping through the tunnel, but any real work causes it to lock up. Is this an MTU problem? =

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<p>Probably. It's best to change the <strong>mssfix</strong> parameter rather than directly changing the MTU of the TUN/TAP adapter. For example:</p>
<blockquote>
<pre><strong>mssfix 1200</strong></pre>
</blockquote>
<p>You could also combine this with:</p>
<blockquote>
<pre><strong>fragment 1200</strong></pre>
</blockquote>
<p>Note however that <strong>fragment</strong> will exact a performance penalty.</p>
<p>Common values to try for <strong>mssfix</strong>/<strong>fragment</strong>: 1200, 1300, or 1400.</p>
<p>Note that while <strong>mssfix </strong>only needs to be specified on one side of the connection, <strong>fragment</strong> should be specified on both.</p>
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