Disable TCP/53

Mark_Andrews at isc.org Mark_Andrews at isc.org
Thu Feb 21 02:33:22 UTC 2002

> Hi, our firewall keeps detecting and rejecting TCP/53 queries.
> Does bind by default use TCP/53 and UDP/53? Is there any way to disable
> TCP/53, thus enabling UDP/53?

	If your firewall keeps getting queries for TCP/53 then in all
	probability you are sending back responses that require TCP
	to complete.  DNS defaults to using UDP and only uses TCP if
	it is required (AXFR, answer too large to fit in a UDP response)
	or is specifically requested.

Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at isc.org

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