[nsd-users] failed writing to tcp: Broken pipe

Anand Buddhdev anandb at ripe.net
Thu Oct 6 12:39:41 UTC 2011

On 06/10/2011 14:24, Michael Tokarev wrote:

Hi Michael,

> But should the "client" NSD be doing like that?  Maybe it is better
> to query for SOA first, instead of asking AXFR right away, and just
> closing the connection when already up to date?

NSD does this deliberately; it has been documented in the file
NSD-FOR-BIND-USERS in the documentation. Here's the relevant extract:

"8. AXFR behaviour.

To do a manual AXFR, nsd-xfer will perform like the BIND tools. But,
the initial query for the SOA is done by TCP, where the BIND tools
use UDP for that SOA query. According to RFC (1034, 1035) specs, both
UDP and TCP for the initial SOA probe are OK.

An AXFR initiated by the built-in transfer process will not start with a
SOA query at all.  The first packet of the AXFR transfer will be used
to determine the SOA version number in that case.  This is a conscious
breach of RFC spec to ease implementation and efficiency."


Anand Buddhdev

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