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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: maybe a dumb idea on how to fix the dns problems i don't know....
On 10 Aug 2008, at 01:45, Paul Vixie wrote: SYN flooding is a specific instance of "have to hold too much state" whereas It may be worth clarifying that "not considering TCP mandatory" above is an implementation/operational choice, and not something that seems to be clearly endorsed by RFC 1035, such as it is. There are a lot of people who insist that TCP transport is used for nothing other than zone transfers in the DNS, and they do so not out of concern over potential TCP state explosion on their servers but instead because "that's what the last guy told me". That kind of reasoning doesn't need a bigger posse. Joe 4.2. Transport The DNS assumes that messages will be transmitted as datagrams or in a byte stream carried by a virtual circuit. While virtual circuits can be used for any DNS activity, datagrams are preferred for queries due to their lower overhead and better performance. Zone refresh activities must use virtual circuits because of the need for reliable transfer. The Internet supports name server access using TCP [RFC-793] on server port 53 (decimal) as well as datagram access using UDP [RFC-768] on UDP port 53 (decimal).
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