[Forum FAQ] DNS request timed out by nslookup when the first forwarder is down

symptom

think scenario below:

using windows server 2008 r2 dns server. first forwarder of dns server down.

timeout occurs when dns client queries by nslookup.

cause

how long dns server wait forwarders depends on value of forwarding timeout. (figure 1)

default value 3 seconds on windows server 2008 r2. however, default time-out period of nslookup 2 seconds. (figure 2)

figure 1

figure 2

when nslookup timeouts, dns server still waiting first forwarder.

resolution

may shorten forwarding timeout period of dns server or increase time-out period of nslookup.

shorten forwarding timeout period, please follow steps below:

1. click start, click run, type dnsmgmt.msc, , press enter. dns manager console open.

2. in console tree, right-click name of dns server , click properties.

3. on forwarders tab, click ip address of forwarder wish configure, , click edit.

4. type forwarding timeout value next number of seconds before forward queries time out , click ok twice. default, dns server waits 3 seconds response 1 forwarder ip address before tries forwarder ip address.

note: forwarding timeout value should 2 10 seconds.

increase timeout period of nslookup, please run follow commands:

nslookup

set timeout=5

hostname want query

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Windows Server  >  Platform Networking