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It's somewhat common ISPs to intercept DNS queries at port 53 and resolve them at their own.
To check if your ISP is intercepting your DNS queries just type this command in the terminal.
"#.abc" it's an OK answer.
But if you get something like "I am not an OpenDNS resolver.", yep, you are beign cheated by your ISP.
This removes the enclosing quotation marks ("), and sticthes the different packets together, e.g. '
Occasionally, to force zone updating, cache flush is necessary. This command is better than restart the mydns daemon.
Occasionally, to force zone updating, cache flush is necessary. Use this command is better than restart the Bind9 process.
Change the $domain variable to whichever domain you wish to query.
Works with the majority of whois info; for some that won't, you may have to compromise:
domain=google.com; for a in $(whois $domain | grep "Domain servers in listed order:" --after 3 | grep -v "Domain servers in listed order:"); do echo ">>> Nameservers for $domain from $a
Note that this doesn't work as well as the first one; if they have more than 3 nameservers, it won't hit them all.
As the summary states, this can be useful for making sure the whois nameservers for a domain match the nameserver records (NS records) from the nameservers themselves.
Simple command to trace a DNS query from the root all the way to the authoritative servers.
Instead of opening your browser, googling "whatismyip"...
Also useful for scripts.
dig can be found in the dnsutils package.
Shorter version, works with multiple words.
Will edit *.db files in the same directory with todays date. Useful for doing a mass update to domains on a nameserver, adding spf records, etc.
Looks for a string starting with 200 or 201 followed by 7 numbers, and replaces with todays date. This won't overwrite Ip's but i would still do some double checking after running this.
Make sure your server's date is correct, otherwise insert your own serial number.
should usually follow this command.
The +short option should make dig less chatty.
I'm just a simple programmer. I find dig too verbose. host tells me alias(es) and IP address in a quick to grok format with nothing special to remember for input parameters.
Mostly for Norwegians, but easily adoptable to others. Very handy if you are brainstorming for a new domainname.
Will only display the available ones..
You can usually do this better with dig, but if you dont have dig, or the TLD only have an online service to check with, this will be usefull..
This command uses nmap to perform reverse DNS lookups on a subnet. It produces a list of IP addresses with the corresponding PTR record for a given subnet. You can enter the subnet in CDIR notation (i.e. /24 for a Class C)). You could add "--dns-servers x.x.x.x" after the "-sL" if you need the lookups to be performed on a specific DNS server.
On some installations nmap needs sudo I believe. Also I hope awk is standard on most distros.