still seeing some delays in lookups

Re: still seeing some delays in lookups

From:

Date:

Time:

It's possible that the EDNS (extended DNS) packet size is an issue.
Unfortunately, the ends-udp-size option is not yet compatible with
QuickDNS, because QuickDNS Remote won't recognize it and will have a
problem.

BIND 9.3.0 can be compiled without this feature. We can create a
compiled version like that for anyone who'd like to try it and report
back whether it helps.

The issue here is that, before EDNS, UDP packets in DNS use were
limited to 512 bytes. This is because, historically, the UDP
transport layer was limited to 512 bytes per packet. EDNS allows a
sort of negotiation between two DNS servers to determine optimal
packet size (i.e. the largest size of packet that will arrive intact
at the other end). These limits are now being expanded.

With EDNS, the servers at either end can negotiate a larger maximum
packet size. Unfortunately, this takes a little time. Fortunately,
the information can be cached.

Chris Buxton
Men & Mice - Making DNS Easy
Customer Service and Sales Engineer

At 2:37 PM -0800 11/12/04, Jody McAlister wrote:
>The mac os x server list had a "fix" which goes one step beyond the
>fix that was given here. I still see a lookup issue, less than
>before (but I am using firefox and Safari which everybody seem to
>say have that problem currently), but the lookups still seem a
>little slower than what I'm used to as well.
>
>Here is an email I pasted in about making an adjustment to the udp
>packet that they claim solved their problem. Does this seem like a
>solution or just an unneccessary extra step. I don't see that he
>tried with bind 9.3.0 before changing the packet size.
>
>******************************************************************
>Hello everyone,
>
>Thanks for the replies from all. It does seem the DNS timeout issue I
>mentioned this morning isn't OS X Server related. In fact, it seems to be
>some type of bug involving BSD, IPv6 and Bind 9.2.x... Apparently some of
>the root servers started issuing IPv6 replies in the past few weeks
>causing the issue to crop up. There is a good discussion in this thread
>here:
>http://discussions.info.apple.com/webx?14@123.Votva3t2BDi.0@.689de754/0
>
>While not a "proper" solution, my solution to this problem was to compile
>Bind 9.3.0 on our XServe. I renamed the old named binary and put the new
>one in its place. Also, I edited the system startup script so it launches
>bind -4 (IPv4 support ONLY) instead of just bind. Lastly, I changed the
>edns-udp-size to limit the packet size to 512 bytes. All of these
>together have solved this issue, at least in our environment.
>
>I encourage anyone experiencing the original symptoms to check out the
>discussion linked above and try out the fix I did.
>
>Thanks everyone
>Mike

Sales:
888/4-DPOINT

Support:
858/452-3696