Intradomain DNS Anycast revisited
just me
matt at snark.net
Sat Mar 26 21:41:24 UTC 2005
It has been my experience in the deployment of such anycasted dns
server pods that pushing ospf from the dns server hosts introduces
complexity and reduces reliability to the point that other, simpler
solutions become much more attractive.
You should also take a moment to take a look at your spanning tree
configuration, depending on how you care configuring your switches.
matto
On Fri, 25 Mar 2005, Joe Shen wrote:
I'm trying to set up a anycast DNS server farm for
customer service. In order to improve availability, we
plan to install those servers in
one LAN which has the similar structure like :
server-(1,3)---switch1---router-1---(outside)
|
|
server-(2,4)---switch2---router-2---(outside)
The four unix servers are all unix boxes, switch-1 &
switch-2 are interconnected to guarantee the
availability. BIND is to be used as
DNS cache server software, Quagga OSPFD is used to be
routing software.
According to above configuration, both routers will
know multiple paths to dns cache server, while dns
cache server should know two
paths to outside network. Here comes my questions:
1) should each dns cache server be configured a static
default route (0.0.0.0/0.0.0.0)? If server-(1,3) is
configured statically to use
router-1 as default router, will Quagga make it use
router-2 when router-1 is not reachable?
2) If each server is configured two default router (
router-1 &
router-2), or each server learn route 0.0.0.0/0.0.0.0
by OSPF ( our border router inject default route into
OSPF ); there should be
two equal cost path to 0.0.0.0/0.0.0.0 on each DNS
server, the DNS server should disperse any outgoing
packets onto the two paths, will
that do harm to DNS service ?
3) Is there any requirement on BIND to fit to such
multipath routing situation?
Joe
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