Free Public DNS Server

Service provider: Google

• 8.8.8.8
• 8.8.4.4

Service provider: ScrubIt
Public dns server address:

• 67.138.54.100
• 207.225.209.66

Service provider:dnsadvantage
Dnsadvantage free dns server list:

• 156.154.70.1
• 156.154.71.1

Service provider:OpenDNS
OpenDNS free dns server list:

• 208.67.222.222
• 208.67.220.220

Service provider: vnsc-pri.sys.gtei.net
Public Name server IP address:

• 4.2.2.1
• 4.2.2.2
• 4.2.2.3
• 4.2.2.4
• 4.2.2.5
• 4.2.2.6

DNS cache > How to Flush DNS in Different OS’es?

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There is some ways you can make DNSFLUSH on several operating systems, and here you will se some of that examples.
Most DNS clients cache the results of name resolution requests. This speeds up name resolution if multiple lookups are done to the same address, such as is common when browsing the web. Sometimes a bad
DNS entry will be cached and you will need to either flush the DNS cache to get rid of it, or wait up to 24 hours for it to be dropped from the cache automatically.

• How to Flush DNS in Linux

In Linux, the nscd daemon manages the DNS cache. To flush the DNS cache, restart the nscd daemon.
To restart the nscd daemon, use the command


#$: /etc/rc.d/init.d/nscd restart

• How to Flush DNS in Mac OSX

In Mac OSX, you can use the command lookupd -flushcache to flush the DNS resolver cache.
bash-2.05a$ lookupd -flushcache

• How to Flush DNS in Microsoft Windows

In Microsoft Windows, you can use the command


C:> ipconfig /flushdns to flush the DNS resolver cache.


Windows IP Configuration Successfully flushed the DNS Resolver Cache.




You can also use the command


C:> ipconfig /displaydns to view the DNS resolver cache.

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cache, dns, Linux, MacOSX, Windows

What is a DNSBL?.

What is a DNS BlackList?
by Morten Holmensen

A DNSBL is a DNS (domain name service)-based spam blocking list. Some people call them blacklists, while others call them blocklists.

These blacklists are IP address-based. This means that they contain IP addresses, generally of email servers that you might receive spam from, or that the blacklist maintainer has indeed received spam from. There are dozens of such lists available, all compiled with different criteria, at every conceivable point in the sanity spectrum. Some lists work better than others, and some list maintainers are more trustworthy and respectable than others.

The original (and still primary) use for DNSBLs is to block mail. Most mail servers nowadays have DNSBL support (either built in, or through use of a plug-in) that allows a mail server administrator to block mail from sites listed on a specific DNSBL. The site would choose to do this as part of their attempt to reduce the amount of spam their users would receive.

More recently, DNSBLs are often used as a part of spam scoring system, such as SpamAssassin. If you’re listed on a spam blacklist that is referenced in a spam scoring system, your spam score could be increased by some amount. (The amount varies and is often configurable.) If that, in addition to other scoring tests performed, makes an email’s score rise above a certain level, it could be discarded, or routed to the spam folder.

Note: you might hear people refer to “RBLs” when talking about spam blocking. The first DNSBL was called the RBL, created by a company I once worked for, the Mail Abuse Prevention System (MAPS). MAPS claims “RBL” as a service mark, but as far as I can tell, anybody using the term RBL is usually using it interchangeably with DNSBL.