[TriLUG] OT: RR Networking Question
mmueller at signalnetware.com
Thu Apr 11 09:22:58 EDT 2002
On Thursday 11 April 2002 09:37 am, you wrote:
> On Thu, 2002-04-11 at 05:34, M. Mueller wrote:
> > I have Earthlink DSL. The DNS servers take a break every now and then.
> > There are two servers, so I ping one and then the other and compare. I
> > don't know a lot about DNS but they seem to throttle every request you
> > make - even if you "ping 188.8.131.52" for example, the DNS will look
> > "222.111.555.2" up and you will take a delay.
> That would be interesting, considering that if you give ping, or
> any other program an ip address *it doesn't look it up in DNS*!
Sorry for the inaccuracy. It's been a while since I've had the problem. I
notice the problem when I ssh2 out to some ip address. Using Ethereal, I see
repeated pokes into the DNS. If the DNS is being slow, then it appears that
I cannot connect to the address. Then I turn off the "nameserver" lines in
/etc/resolve.conf and try ssh2 again, I don't see the pokes into the DNS and
away I go to the ip address. Having the DNS involved with ftp or scp between
machines on the same subnet drive me bonkers until I figured out that I
needed to control access to the Earthlink DNS in the /etc/resolv.conf.
Earthlink is probably relieved that I am not hitting there DNS with unneeded
queries. I wonder what percentage of ISP DNS queries come from private LAN
I have a LAN with 6 machines.
- 2 need DNS services for email and surfing. One is W98. THe other is
Mandrake 8.1. These are allowed to used the DNS always.
- 1 needs ssh acccess to the world (no DNS required) and occasional
ftp/surfing (DNS required occasionally). I manually turn on DNS access when
I need it by modifying /etc/resolv.conf. Very crude, I think.
- The remaining 3 need no off-LAN access. /etc/resolv.conf contains "search
THis is admittedly a crude setup, but I avoid hitting the DNS unnecessarily
and I don't have much administration in the 3 boxes that run exclusively on
the private LAN.
Any advice on reconfiguring would be most appreciated. Maybe the machine
needing occasional DNS access should have a local DNS to provide routing
answers regarding known addresses (LAN and known WAN addresses)?
More information about the TriLUG