override ttl=0

[Herve Guehl]

Unfortunatly, The manufacturer is CISCO...
http://www.cisco.com/en/US/products/ps6553/products_white_paper09186a008011ff51.shtml
It's a pain when your working with partners that use this
technology...(Obviously I have no choice and bo weight about it :) )
regard.
Herve Guehl



On Dec 21, 2007 10:51 PM, Mark Andrews <Mark_Andrews at isc.org> wrote:

>
> > Hi everybody,
> > I'm getting troubles with a DNS-ALG machine that send ttl=0 for every
> > question I send to it.
> > I browsed archive but did not find any solution to my problem.
> > I just need to override ttl for A record when the ttl=0.
> > Here a patch for bind 9.3.3rc2 (redhat 5.0).
> > I know, that TTL should not be overrided, but in some case this
> > functionality can be helpfull.
>
>        Tell us the manufacture of the DNS-ALG so we can all avoid
>        such a broken product.  The DNS requires caching to work.
>        Any DNS-ALG that don't pass on the TTL is broken.
>
> > The status of this patch is 'works for me'.
> >
> > Please let me know if there is another implementation
> >
> > Regard
> > Hervé Guehl
> >
> > Note : dont blame me if i'm not using the right list, just say me where
> I
> > should write
> >
> >
> >
> > diff -urN bind-9.3.3rc2.ori/bin/named/server.c bind-9.3.3rc2
> > /bin/named/server.c
> > --- bind-9.3.3rc2.ori/bin/named/server.c        2006-05-24 06:30:
> > 24.000000000 +0200
> > +++ bind-9.3.3rc2/bin/named/server.c    2007-12-18 22:01:47.000000000+0100
> > @@ -1245,6 +1245,11 @@
> >         result = ns_config_get(maps, "max-cache-ttl", &obj);
> >         INSIST(result == ISC_R_SUCCESS);
> >         view->maxcachettl = cfg_obj_asuint32(obj);
> > +
> > +       obj = NULL;
> > +       result = ns_config_get(maps, "override-zero-cache-ttl", &obj);
> > +       INSIST(result == ISC_R_SUCCESS);
> > +       view->overridezerocachettl = cfg_obj_asuint32(obj);
> >
> >         obj = NULL;
> >         result = ns_config_get(maps, "max-ncache-ttl", &obj);
> > diff -urN bind-9.3.3rc2.ori/lib/dns/include/dns/view.h bind-9.3.3rc2
> > /lib/dns/include/dns/view.h
> > --- bind-9.3.3rc2.ori/lib/dns/include/dns/view.h        2004-03-10
> 03:55:
> > 58.000000000 +0100
> > +++ bind-9.3.3rc2/lib/dns/include/dns/view.h    2007-12-18 22:02:
> > 01.000000000 +0100
> > @@ -116,6 +116,7 @@
> >         isc_boolean_t                   requestixfr;
> >         isc_boolean_t                   provideixfr;
> >         dns_ttl_t                       maxcachettl;
> > +       dns_ttl_t                       overridezerocachettl;
> >         dns_ttl_t                       maxncachettl;
> >         in_port_t                       dstport;
> >         dns_aclenv_t                    aclenv;
> > diff -urN bind-9.3.3rc2.ori/lib/dns/resolver.c bind-9.3.3rc2
> > /lib/dns/resolver.c
> > --- bind-9.3.3rc2.ori/lib/dns/resolver.c        2006-08-31 05:57:
> > 11.000000000 +0200
> > +++ bind-9.3.3rc2/lib/dns/resolver.c    2007-12-18 22:02:56.000000000+0100
> > @@ -3537,6 +3537,11 @@
> >                         rdataset->ttl = res->view->maxcachettl;
> >
> >                 /*
> > +                 * HGU configure minimum ttl if ttl=0 for A record
> > +               */
> > +               if  ( (rdataset->ttl == 0) && (rdataset->type ==
> > dns_rdatatype_a) )
> > +                        rdataset->ttl > res->view->overridezerocachettl;
> > +               /*
> >                  * If this rrset is in a secure domain, do DNSSEC
> validation
> >                  * for it, unless it is glue.
> >                  */
> > diff -urN bind-9.3.3rc2.ori/lib/isccfg/namedconf.c bind-9.3.3rc2
> > /lib/isccfg/namedconf.c
> > --- bind-9.3.3rc2.ori/lib/isccfg/namedconf.c    2006-03-02 01:37:
> > 20.000000000 +0100
> > +++ bind-9.3.3rc2/lib/isccfg/namedconf.c        2007-12-19 15:11:
> > 49.000000000 +0100
> > @@ -715,6 +715,7 @@
> >         { "lame-ttl", &cfg_type_uint32, 0 },
> >         { "max-ncache-ttl", &cfg_type_uint32, 0 },
> >         { "max-cache-ttl", &cfg_type_uint32, 0 },
> > +       { "override-zero-cache-ttl", &cfg_type_uint32, 0 },
> >         { "transfer-format", &cfg_type_transferformat, 0 },
> >         { "max-cache-size", &cfg_type_sizenodefault, 0 },
> >         { "check-names", &cfg_type_checknames, CFG_CLAUSEFLAG_MULTI },
> >
> >
> --
> Mark Andrews, ISC
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at isc.org
>