Search Again: Re: Was RFC1912. I found it From: Men & Mice Support Date: Monday, July 14, 2003 Time: 4:10:34 pm A few points: - While TCP connections are permitted for DNS queries, no DNS server uses them. And while Bind and QuickDNS Server (for classic Mac OS) listen for them, not all DNS servers do, precisely because they're not required for production DNS use. (Some diagnostic programs do use them.) - The DNS "recommendation" RFC's are mutually contradictory, so pick one or ignore them all. Citing one as actual best practice is pretty much pointless. Note that the default SOA values used by QuickDNS are those suggested by one of these recommendation RFC's, but, again, we picked the one we felt was most rational. - The root, com, and net zones list 13 servers, because that's all they could cram into a 512-byte packet. However, some pretty simple compression schemes are used in DNS packets, so packet size doesn't scale with zone name length. Also, different servers return different amounts of data in a given packet. If you want to know what packet size you're seeing, use the 'dig' command line tool to ask one of your authoritative servers for the address of your web server. The packet size is listed in the result. - If a response does happen to overflow a packet, that doesn't mean that no data is returned, and that the querying server *must* resort to TCP. It simply means that some of the end is cut off - usually the A records for name servers. This isn't the end of the world, but it's best not to have so many NS records that you lose all (or even most) of the associated A records. ____________________________________________________________________ Chris Buxton Men & Mice Customer Support Specialist Making DNS Easy At 5:37 PM -0500 7/14/03, Mia's Virtual Post Office wrote: >Ok, I found it.. Has anyone seen any practical/real world experience >with any actual problems occurring? > >" Make sure your parent domain has the same NS records for your zone as > you do. (Don't forget your in-addr.arpa zones too!). Do not list > too many (7 is the recommended maximum), as this just makes things > harder to manage and is only really necessary for very popular top- > level or root zones. You also run the risk of overflowing the 512- > byte limit of a UDP packet in the response to an NS query. If this > happens, resolvers will "fall back" to using TCP requests, resulting > in increased load on your nameserver." > > > > > >Regards, >Jeremy Anthony Kinsey > e-mail: jer@mia.net >________________________________________________________ >Bella Mia, Inc. www.mia.net >401 Host Drive www.dslone.com >Lake Geneva, WI. 53147 www.hostdrive.com >Phone: (262)248-6759 www.bella-mia.com >Fax: (262)248-6959 www.thednsplace.com

Messages In This Thread: Was RFC1912. I found it by Mia''s Virtual Post Office on Jul 14, 2003 at 3:48:39 pm Re: Was RFC1912. I found it by Men & Mice Support on Jul 14, 2003 at 4:10:34 pm