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DNS hijacking, DNS poisoning, or DNS redirection is the practice of subverting the resolution of Domain Name System (DNS) queries. [1] This can be achieved by malware that overrides a computer's TCP/IP configuration to point at a rogue DNS server under the control of an attacker, or through modifying the behaviour of a trusted DNS server so that it does not comply with internet standards.
A reverse DNS lookup is a query of the DNS for domain names when the IP address is known. Multiple domain names may be associated with an IP address. The DNS stores IP addresses in the form of domain names as specially formatted names in pointer (PTR) records within the infrastructure top-level domain arpa. For IPv4, the domain is in-addr.arpa.
In computer networks, a reverse DNS lookup or reverse DNS resolution ( rDNS) is the querying technique of the Domain Name System (DNS) to determine the domain name associated with an IP address – the reverse of the usual "forward" DNS lookup of an IP address from a domain name. [ 1] The process of reverse resolving of an IP address uses PTR ...
IPv4 address exhaustion is the depletion of the pool of unallocated IPv4 addresses. Because the original Internet architecture had fewer than 4.3 billion addresses available, depletion has been anticipated since the late 1980s when the Internet started experiencing dramatic growth. This depletion is one of the reasons for the development and ...
Used for loopback addresses to the local host [1] 169.254.0.0/16 169.254.0.0–169.254.255.255 65 536: Subnet Used for link-local addresses [5] between two hosts on a single link when no IP address is otherwise specified, such as would have normally been retrieved from a DHCP server 172.16.0.0/12 172.16.0.0–172.31.255.255 1 048 576: Private ...
Make sure the option "Block All Senders Except Contacts" under "Mail Settings --> Block Senders" is unchecked. If checked, you will not receive messages from anyone not in your contacts. Messages are often delivered right way though very rarely there may be a delay in transit. This is usually due to problems on the mail server, heavy internet ...
Google, a major provider of services on the Internet, experimented with using a type of DNS allowlisting on a per-ISP basis to prevent this until the World IPv6 Launch. In the DNS allowlisting approach, ISPs are determined from DNS lookup source IP addresses by correlating them with network prefixes derived from routing tables .
Microsoft Windows, IBM OS/2: Proprietary commercial software. ReactOS: GNU General Public License. nslookup (from name server lookup) is a network administration command-line tool for querying the Domain Name System (DNS) to obtain the mapping between domain name and IP address, or other DNS records .