Wednesday, January 7, 2015

DNS troubleshooting tools and tips - nslookp

if you are on Windows, dig is not there, you can do most DNS query through nslookup.

to see the DNS cache on your local server,  run “ipconfig /displayDNS”

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same thing, ipconfig /flushDNS to purge the cache.

to see name server of a giving domain

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to see all infomration like root server, try nslookup , set all

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to see mx record of amazon.

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to see the spf record?

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what about debug information

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to see all information

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to see all the ips of a domain or even this history.

https://www.virustotal.com/en/domain/dl.dropbox.com/information/

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DNS troubleshooting tools and tips - dig

To see top level Name Servers,  dig –t ns com

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If we want to see what’s are the name server of Google by asking any top level com servers.

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now we can ask any nameserver of google, what’s are the ip of www.google.com

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we can also using host command to get the ip or alias information

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we can see the alias gmail.google.com

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if we want to see some debug information. we can put debug there

[~]dig +trace  -t mx  dropbox.com

; <<>> DiG 9.8.3-P1 <<>> +trace -t mx dropbox.com
;; global options: +cmd
.            15634    IN    NS    a.root-servers.net.
.            15634    IN    NS    b.root-servers.net.
.            15634    IN    NS    c.root-servers.net.
.            15634    IN    NS    d.root-servers.net.
.            15634    IN    NS    e.root-servers.net.
.            15634    IN    NS    f.root-servers.net.
.            15634    IN    NS    g.root-servers.net.
.            15634    IN    NS    h.root-servers.net.
.            15634    IN    NS    i.root-servers.net.
.            15634    IN    NS    j.root-servers.net.
.            15634    IN    NS    k.root-servers.net.
.            15634    IN    NS    l.root-servers.net.
.            15634    IN    NS    m.root-servers.net.
;; Received 228 bytes from 8.8.8.8#53(8.8.8.8) in 29 ms

com.            172800    IN    NS    a.gtld-servers.net.
com.            172800    IN    NS    b.gtld-servers.net.
com.            172800    IN    NS    c.gtld-servers.net.
com.            172800    IN    NS    d.gtld-servers.net.
com.            172800    IN    NS    e.gtld-servers.net.
com.            172800    IN    NS    f.gtld-servers.net.
com.            172800    IN    NS    g.gtld-servers.net.
com.            172800    IN    NS    h.gtld-servers.net.
com.            172800    IN    NS    i.gtld-servers.net.
com.            172800    IN    NS    j.gtld-servers.net.
com.            172800    IN    NS    k.gtld-servers.net.
com.            172800    IN    NS    l.gtld-servers.net.
com.            172800    IN    NS    m.gtld-servers.net.
;; Received 489 bytes from 128.63.2.53#53(128.63.2.53) in 144 ms

dropbox.com.        172800    IN    NS    ns-564.awsdns-06.net.
dropbox.com.        172800    IN    NS    ns-315.awsdns-39.com.
dropbox.com.        172800    IN    NS    ns-1162.awsdns-17.org.
dropbox.com.        172800    IN    NS    ns-1949.awsdns-51.co.uk.
;; Received 198 bytes from 192.52.178.30#53(192.52.178.30) in 167 ms

dropbox.com.        3600    IN    MX    1 aspmx.l.google.com.
dropbox.com.        3600    IN    MX    10 aspmx2.googlemail.com.
dropbox.com.        3600    IN    MX    10 aspmx3.googlemail.com.
dropbox.com.        3600    IN    MX    5 alt1.aspmx.l.google.com.
dropbox.com.        3600    IN    MX    5 alt2.aspmx.l.google.com.
dropbox.com.        172800    IN    NS    ns-1162.awsdns-17.org.
dropbox.com.        172800    IN    NS    ns-1949.awsdns-51.co.uk.
dropbox.com.        172800    IN    NS    ns-315.awsdns-39.com.
dropbox.com.        172800    IN    NS    ns-564.awsdns-06.net.
;; Received 296 bytes from 205.251.194.52#53(205.251.194.52) in 21 ms

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