At Bobcares, we often deal with account migrations for web hosts, in our role as Outsourced Tech Support engineers. A common concern users have during such migrations is a way to verify their websites before they go live.
Today, we’ll discuss about how to temporarily access websites in two ways – Using cPanel temporary URL and local DNS hosts file – and our recommendations regarding the two options. (more…)
Failed to start service : Failed to start BIND : Starting named: [FAILED]
This is a commonly seen errors in web servers, when your DNS service fails to start. As DNS is vital for your websites to resolve, ‘named failed’ obviously means your websites have gone down too.
DNS is the basis of most internet applications – emails, messengers, web site browsing, etc. But we often tend to miss out the presence of this extensively used service. As a result, server administrators overlook the vulnerabilities in dns service and hackers easily exploit this aspect. (more…)
On 28th July Internet Systems Consortium announced a critical vulnerability (CVE-2015-5477) in all BIND DNS server versions from 9.1.0 to 9.9.7-P1 and 9.10.2-P2. It allows a remote attacker to exploit an error in handling TKEY queries to launch a Denial of Service (DoS) attack which will cause the BIND DNS server to crash. If your cPanel/WHM, Odin Plesk or DirectAdmin servers are not patched, you should consider them vulnerable. (more…)
On 28th July Internet Systems Consortium announced a critical vulnerability (CVE-2015-5477) in all BIND DNS server versions from 9.1.0 to 9.9.7-P1 and 9.10.2-P2. It allows a remote attacker to exploit an error in handling TKEY queries to launch a Denial of Service (DoS) attack which will cause the BIND DNS server to crash. (more…)
Gmail is one of the most reliable and reputable mail services. So it piqued our tech team when our billing division reported that Google seemed to think our server is a spam source.
We routinely keep track of all spam black lists, and were quite sure that the server reputation was not affected. The mails that were sent to other major providers like Yahoo, Hotmail, etc were not affected. Only Google was sending all our mails to the spam folder.
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The email header analysis
OK. So, it could be because of the recent HTML changes in the invoice, right? We needed to test that, and sent a plain text mail to our Gmail account. It still landed in the spam box. Hmm..
It was time for a more methodical analysis of mail headers.
Most of us might have come across instances where mails from our domain are marked as spam even though it is legitimate. This article describes few settings that can be implemented in order to decrease the chances of mails originating from your domain being marked as spam.
Spamming can be prevented to a great extend by using anti-spamming DNS records such as SPF, DomainKey and reverse DNS.
Sender Policy Framework (SPF) records helps to prevent spoofing of mails by verifying the sender’s IP address. SPF record allows domain owners to specify IP address from which mails will originate, so that receivers verifying the SPF records can reject messages from unauthorized sources before receiving the body of the message.
IPv4 and IPv6 are addressing schemes to direct traffic across the Internet. IPv6 is the next generation in the Internet Protocol. Currently, almost all of the Internet traffic is directed using IPv4 address. It provides 2^32 (4,294,967,296) possible addresses. However, the increase in demand has lead to a shortage in the IP addresses. A solution for this shortage is the IPv6 scheme, which provides upto 2^128 addresses. It will also improve performance of the network by providing features like built in support for virtual private network protocols, multicast groups etc.
Ok, now that we know what IPv6 IP address are all about in part I and II, lets take a look at what it would be like using them for sites hosted on your server.
I know I said I’d talk about IPv6 DNS records in this post, but I realized that we’d have to cover a few basics first. So lets cover those first before moving on…