RES_DFLRETRY in resolv.h

[Rostislav Krasny]

Hi,

According to resolver(5) manual page the number of times the resolver
will send a query to each of its name servers before giving up and
returning an error to the calling application is a RES_DFLRETRY defined
in resolv.h. For years FreeBSD had no RES_DFLRETRY macro defined in
resolv.h and had used a hardcoded constant, until Yar Tikhiy fixed it:

http://docs.freebsd.org/cgi/mid.cgi?200409091739.i89HdlwM019548
http://docs.freebsd.org/cgi/mid.cgi?200409091742.i89HgIan019681
http://docs.freebsd.org/cgi/mid.cgi?200409091719.i89HJRGu019026

Other systems and BIND9's internal resolver define the RES_DFLRETRY
as 2, but in FreeBSD that macro is 4. Why it's so big? I think it had
been inherited from old BIND4's resolver. Could the RES_DFLRETRY be
decreased from 4 to 2 ?

Current value of RES_DFLRETRY can make host unreachable. Read a
bin/62139 PR and "SSH login takes very long time...sometimes" threads on
freebsd-stable mailing list.

Thanks