----- Original Message ----- From: "Peter Poeml" <poeml@suse.de> To: <opensuse@opensuse.org> Sent: Wednesday, February 11, 2009 8:50 PM Subject: Re: [opensuse] round robin dns for the repo mirrors
Hi Brian,
[...] No, seriously, I can tell you what to do. Use 'host' and look at the returned data:
from the US, you'll see: # host mirrors.kernel.org mirrors.kernel.org is an alias for mirrors.geo.kernel.org. mirrors.geo.kernel.org is an alias for mirrors.us.kernel.org. mirrors.us.kernel.org has address 149.20.20.135 mirrors.us.kernel.org has address 204.152.191.39
As you see, the hostname points to some other hostname, and in each case there are two of them. The two entries are treated equivalently by resolvers and they return them in random order, so any of them gets used. Which is the DNS round robin.
You see the DNS Aliases, though, so you can of course use them directly.
[...]
Ah, I nearly forgot one crucial bit. Use a reverse lookup to see whether there's a hostname record for the rr'd IP addresses:
% host 204.152.191.39 39.191.152.204.in-addr.arpa is an alias for 39.32-27.191.152.204.in-addr.arpa. 39.32-27.191.152.204.in-addr.arpa domain name pointer mirrors2.kernel.org. % host 149.20.20.135 135.20.20.149.in-addr.arpa is an alias for 135.128-27.20.20.149.in-addr.arpa. 135.128-27.20.20.149.in-addr.arpa domain name pointer mirrors1.kernel.org.
Et voila, there we see that there's a hostname that can be used to access any of the machines directly:
% host mirrors1.kernel.org. mirrors1.kernel.org has address 149.20.20.135 [...] % host mirrors2.kernel.org. mirrors2.kernel.org has address 204.152.191.39 [...]
This is exactly what I use to scan those two hosts.
Nice run-down. Thanks much. -- Brian K. White brian@aljex.com http://profile.to/KEYofR +++++[>+++[>+++++>+++++++<<-]<-]>>+.>.+++++.+++++++.-.[>+<---]>++. filePro BBx Linux SCO FreeBSD #callahans Satriani Filk! -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org