Maximum number of updates in a single transaction

Mark Andrews Mark_Andrews at
Fri Feb 10 23:14:11 UTC 2006

> Hi,
> We are implementing a new service that requires a substantial number 
> of dynamic updates to be performed on a zone. We are talking of 2K 
> updates in a single dynamic update transaction.
> We made some tests with Bind 9.3.2 by sending 60 domain updates in a 
> single transaction (TCP) and everything works correctly.
> RFC2136 specify a 16 bit limit to UPCOUNT section in the header, so I 
> assume that the limit of updates that I can send on a single 
> transaction is 2^16.
> What is your recommendation of the maximum number of updates in a 
> single transaction?
> I believe that ISC makes validation tests with each BIND release. How 
> many dynamic updates are sent in the ISC's validation tests?
> Thank you.
> Gustavo Lozano
> NIC Mexico (ccTLD .mx)

	The limitation is the size of the DNS message.  A individual
	message can be up to 65535 bytes.

Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at

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