On November 8th 2011, the Estonian police, the FBI, and the NASA-OIG arrested seven men in Operation Ghost Click. This group of people operated under the company name Rove Digital, and distributed viruses that changes the DNS settings of victims. The Estonian court found their guilt not proven, but one member later plead guilty in the …
The nslookup command line tool uses your system’s DNS stub resolver by default. This resolver uses your ISP’s DNS servers if you haven’t changed them. You can overwrite this default setting by specifying a DNS server in the command itself. To query a specific DNS server in nslookup, add the server’s IP or hostname at …
This week, Facebook suffered its worst outage since 2008 and was down for six hours. The economic cost of this outage will be large in both dollars and customer goodwill. Facebook will undoubtedly spend many person-hours on post-mortems and repairs to prevent this from happening again. While this was not a DNS issue, it’s worth …
Every TLD registry maintains data about registered domain names. They publish this data over the WHOIS protocol. Currently, 36 registries publish the location of their WHOIS servers using SRV records. For example, the .de TLD registry publishes the location of its WHOIS server in an SRV record: ❯ dig +short _nicname._tcp.de srv 0 0 43 whois.denic.de. I’ve queried …
Your web address or the URL is what people type in their browsers to access your website. This address helps people and search engines to identify you online. As you can guess, this is a pretty important element to nail down when you launch your business. Many businesses mistakenly do not give it the consideration …
An important part of the process of creating a new website, blog, email, or other Internet service is registering the new DNS domain name. Registration inserts the new domain name into the global DNS so that everyone across the Internet can resolve it and make use of its services. You can create a new website …
Each domain name may have only one DMARC record. When you connect multiple email services to a domain name, they will ask you to set different DMARC records. You can merge DMARC records, but that is not always practical. Another solution is subdomains. Each email sender uses their own subdomain and has their own DMARC policy. This eliminates …
Domain-based Message Authentication, Reporting, and Conformance (DMARC) is an email authentication protocol designed to protect domains from phishing attacks and abuse by spammers. A domain may have multiple senders for different types of email, but each domain may have only one DMARC record. For example, a domain may have an on-premise Exchange server for email …
The domain name system (DNS) plays an important role in delivering email. The owner of a domain name (for example: @gmail.com) can specify where mail should be delivered. It can also prove that it has sent an email on behalf of the domain name owner. Other mail servers need some way to look up the email …
Domain-based Message Authentication, Reporting, and Conformance (DMARC) is one of the three pillars of modern email security. DMARC works with Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) to protect against spoofing, spam, and phishing attacks. DMARC adds reporting and policy to email security: DMARC is specified in RFC 7489. How DMARC works The DMARC record for a domain …
