[sf-lug] SF-LUG DNS

[jim]

   jim was studying diligently until the dentist 
pulled out one of his teeth and filled him with 
pain pills. jim will study more in the morning. 



On Tue, 2009-11-17 at 12:17 -0800, Rick Moen wrote:
> Quoting Michael Paoli (Michael.Paoli at cal.berkeley.edu):
> 
> > Yes, definitely still stuff to be done (I keep hoping Jim or someone
> > else will get SF-LUG.COM. DNS squared away before the secondary expires
> > the zone ... but if the timing gets too close on that, I plan to correct
> > it - and in the meantime Jim Stockford and/or other SF-LUG.COM.
> > systems/DNS administrators can contact me if they need assistance or
> > have questions).
> 
> If need be, it's simple to prevent zone expiration by temporarily
> telling the secondary that it's master for the zone (until the
> replacement master is ready).
> 
> > Actually, by coincidence, turns out the "new" (substituted) master DNS
> > server is ... well, will be anyway, on the same IP (host is there, but
> > last I checked it's not yet serving up DNS nor particularly being DNS
> > for SF-LUG.COM.).
> 
> OK, good for me, then.  ;->  Everything should Just Work when Jim has 
> the master DNS back online.
> 
> 
> > # cat var/named/chroot/var/named/sf-lug.com
> > $TTL 86400
> > $ORIGIN sf-lug.COM.
> > @       IN      SOA     ns1.sf-lug.com. jim.well.com. (
> >                         2007102904      ;Serial
> >                         3600            ;refresh period
> >                         3600            ;retry period
> >                         1209600         ;expire period
> >                         10800)          ;minimum TTL period
> > ;
> 
> Minor correction:  The last SOA sub-field hasn't signified "minimum TTL
> period" since BIND4 days.  The above annotation is a dusty holdover,
> probably copied from an old example file, and should be replaced.  The
> new-er purpose of that subfield is "negative TTL" aka "negative
> caching", which is how many seconds a nameserver should cache a NAME
> ERROR (NXDOMAIN) record.
> 
> FYI, the value you specify, 10800 = 3 hours, is the longest time period
> for negative caching allowed by RFCs.  
> 
> FWIW, I tend to use these values in SOAs:
> 
>                         7200                    ; refresh 2 hours
>                         3600                    ; retry 1 hour
>                         2419200                 ; expire 28 days
>                         10800                   ; negative TTL 3 hours
> 
> 
> 
> [snip suggested steps when moving master DNS]
> 
> > Yes, ... not quite the situation in this case.
> 
> True, those remarks having been based on the assumption of moving master
> DNS to a new IP.
> 
> It's still good to let your secondaries know about planned downtime.
> Which of course means it's a good idea to keep contact information in
> your /etc/named.conf[.local].
> 
> 
> 
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