[PLUG] Spotty DNS Resolution
Daniel Hedlund
daniel at digitree.org
Sat Oct 14 23:50:14 UTC 2006
Aaron Ten Clay wrote:
> This is likely your problem. Most DNS servers these days, it seems, give up
> after about 2000ms if they can't get the info you want. Especially when just
> doing forwards. The DNS scheme is that you have multiple servers so if one is
> down/unreachable you can keep trying all the servers for a zone. Since most
> software doesn't seem to do that anymore, your listing a non-DNS server as a
> server for your domain is likely the cause of the problem. Resolvers are
> probably trying that one first, and giving up.
Timeouts could be a very likely issue and may be my main problem. There
is always a possibility on the server that the DNS response might lag by
a couple of seconds. This is because I don't have very much memory on
the machine and some other services on the box might cause BIND to swap
out of memory at the wrong time. Good suggestion; not much I can do
about it besides get more memory or move it to another box (ie. OpenWRT
router or something).
> In cases where I've had no other options, I've run a second IP on one host and
> listed both IPs as the two nameservers for a domain. No redundancy, but at
> least all DNS requests are satisfied if the host is up (and any services on
> that host would be down if the host were down, anyway, negating any benefit
> to redundancy)
This is what I used to do several years ago. Getting a second IP
address in the short term is a no go as I'm getting ready to move in a
couple of days (servers will stay "for now"), but may be viable in a
month or so. When I moved overseas I was able to update Dotster's DNS
server list to only have a single entry so I only had one IP address
there which worked well. When I moved back to Portland and set up a
server here, Dotster had updated their inteface to require a minimum of
two servers (very annoying).
> If all else fails, you could use everydns.net for a secondary server. I've
> used them for a while now without any problems. (Free/donation requested
> service)
I tried a similar service to everydns.net once a couple years ago; I
can't remember the name of it but I don't think it was everydns. I
wound up losing my DNS records for almost a week it suddenly stopped
serving my domain. I will consider trying everydns, thanks.
Cheers,
Daniel Hedlund
daniel at digitree.org
More information about the PLUG
mailing list