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4

You can use the +trace option to dig to see the entire sequence of queries, from your system to root servers, all the way down to the authoritative servers.


3

That is expected behaviour; if you do not allow recursion, BIND wont iterate through the possibilities/servers to eventually got your answer, and thus wont be able to answer. The important part is creating ACLs limiting the networks who can do recursive requests, and avoid an open DNS server that can be and will be abused remotely. I would also advise to ...


3

/etc/resolv.conf is built from pieces that are in the directory /run/resolvconf/interface (actual location on current Debian and Ubuntu) /etc/resolvconf/run/interface (old location, still existing via a symbolic link on Debian). Each piece is named after the interface that it is associated with. When they aren't static, the entries in ...


3

If you don't need resolvconf to manage your /etc/resolv.conf file, the simplest solution is to uninstall resolvconf entirely.


3

For DNS, you need to allow UDP packets between any port on an IP address inside the firewall, and port 53 on an IP address outside the firewall. For HTTPS, you need to allow TCP packets between any port on an IP address inside the firewall, and port 443 outside the firewall, or more rarely any port outside the firewall (some websites are not on the default ...


2

Client doesn't need to know IP address of the DHCP server. Client will send initial packet to all hosts within its subnet using broadcast address 255.255.255.255. For further reading you may refer to official documentation of DHCP protocol https://tools.ietf.org/html/rfc2132 To restart dhcp client on particular network interface (em0in your case), you may ...


2

Look, according to tshark, DNS servers return different protocol messages for your domain names. For does.not.exist you receive DNS 149 Standard query response 0x0d51 No such name. For red3.ethz.ch you receive Standard query response 0xe4db and 0 answers. What is why host returns different codes. As for resolving does.not.exist a DNS server response is: ...


2

The dhclient-script is doing this. It checks to see what nameservers and domains are visible. Sometimes that is useful. According to its manual page, When it starts, the client script first defines a shell function, make_resolv_conf , which is later used to create the /etc/resolv.conf file. To override the default behaviour, redefine this function in ...


1

Yes, use a CNAME record. Exact syntax and details will depend on your software, but basically in place of writing something like this: xx.abc.com. A 192.0.2.1 …you'll write something like this: xx.abc.com. CNAME xx.def.com.


1

The localhost entry is always "the machine you are currently logged in to". It's also referred to as loopback, though that's more the interface name than the host name. The IP address is 127.0.0.1.


1

Reverse records (for IPv4) are stored (backwards) somewhere under the in-addr.arpa zone, which tools like host will handily reverse for you, while other tools may need to be fed the reversed IP address and so forth. % host 8.8.8.8 | awk '{print $NF}' google-public-dns-a.google.com. % host 104.16.117.182 Host 182.117.16.104.in-addr.arpa. not found: ...


1

It is because it is a subdomain. You have to lookup the root part of the domain name: $ whois warwick.ac.uk


1

The only valid WHOIS registrations are for licensed domains only. However, if you own the primary domain, you could setup your own WHOIS server that could be queried for subdomains that you register under you. Code: whois -h whois.yourdomain.com subdomain.yourdomain.com It is not difficult to setup a whois server if you want to maintain one yourself.



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