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Depends what DNS server you are running.
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What if I am using BIND, does is support both TCP and UDP by default? Thanks!
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What if I am using BIND, does is support both TCP and UDP by default? Thanks!

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DNS over TCP is almost never used.<br />
Any server out there supports DNS over TCP but no clients use that by default.<br />
Since it is that rarely used I suspect more problems in there.
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DNS over TCP is almost never used.
Any server out there supports DNS over TCP but no clients use that by default.
Since it is that rarely used I suspect more problems in there.

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It depends on client. Some servers do send chain of UDP packets with huge record...
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It depends on client. Some servers do send chain of UDP packets with huge record...

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I feel by default DNS uses UDP protocol on port 53. Could we configure it to let it use the TCP as well ? /etc/services shows it support both TCP and UDP.<br />

<pre><code id="code-315545">bash-3.00# grep 53 /etc/services 
domain          53/udp
domain          53/tcp
</code></pre>
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I feel by default DNS uses UDP protocol on port 53. Could we configure it to let it use the TCP as well ? /etc/services shows it support both TCP and UDP.

Could we configure DNS to use TCP ?

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