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Showing entries 1 to 21

Displaying posts with tag: dns (reset)

Cloudflare, now offering to be your Single Point of Failure
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There have been many articles about the downtime issue with Cloudflare last week, so I won’t get into the technical details of that. However, there’s the fine print to remember. Consider this a subtle reminder that core Internet infrastructure services like Cloudflare’s DNS-based “Always Online” caching and packet inspection security services do not come with Service Level Agreements even at the “Pro” account level. Even with a Pro account you are paying for a service with no uptime guarantee and you must only hope that it resolves your sites the majority of the time. This is fine, this is what the contract says: no SLA unless you pay for the Business account. An odd naming convention given that most Professionals are using their websites for business and would want the SLA, but I digress.

So,

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DNSaaS application MySQL HA solution with Percona XtraDB Cluster (Galera)
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I haven't written in a while. Some of the reason is that life has been incredibly busy with two young children. The other reason is that I've been busy at work with my team developing HP Cloud DNS, a service that runs in the cloud, as do the various other applications within the Platform as a Service group that I am part of. After a period of rapid development and deployment, Cloud DNS recently went into private beta . The ability to build an cloud application such as this was primarily that I have a great team (Kiall Mac Innes, Simon McCartney and a great product manger Josh Barry) as well as having chosen the right tools and software solutions. For the deployment side of things, Chef, despite frustrations that I have had before getting my mind around it, was a solution that I knew would make it so we could deploy anywhere, as well as being  [Read more...]
The blog was down yesterday
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The brief outage was due to a scheduled move of the servers to a separate rack and subnet dedicated to our work with the Center for Information Assurance & Cybersecurity (ciac) at the University of Washington Bothell (uwb), and a11y.com

I am currently exercising the new (to us) equipment and hope to winnow the less than awesome equipment over the next quarter. I spent the last six months finding the best in breed of the surplussed DL385 and DL380 chassis we (work) were going to have recycled. The team and I were able to find enough equipment to bring up one of each with eight and six gigs of memory, respectively. These will make excellent hypervisors for provisioning embedded instances of Slackware, Fedora, RHEL, CentOS, Debian, FreeBSD, OpenSolaris, OpenIndiana, FreeDOS, etc.

When I initially configured this xen paravirt environment, I failed to plan for integration with libvirt, so I am

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Working with IP's in MySQL and MariaDB - Part 2
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Use DNS directly from your database

mysql> SELECT lookup('localhost');
+---------------------+
| lookup('localhost') |
+---------------------+
| 127.0.0.1 |
+---------------------+
1 row in set (0.00 sec)

mysql> SELECT reverse_lookup('127.0.0.1');
+-----------------------------+
| reverse_lookup('127.0.0.1') |
+-----------------------------+
| localhost |
+-----------------------------+
1 row in set (0.00 sec)

This is how you install these functions.
  • Build udf_example.so which is in your mysql source. (make udf_example.so)
  • Copy the udf_example.so file from your build directory to your plugin_dir.
  • Create the lookup and reverse_lookup


















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    MySQL: Disable DNS Lookups
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    In a small environment, there's very little reason to rely on DNS resolution inside MySQL. You can disable it by adding skip-name-resolve to your my.cnf or by using the --skip-name-resolve command line argument.

    Remember that if you disable DNS lookups, you will need to set permissions using IP addresses rather than host names!

    Clear Windows DNS Server Cache From the CLI
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    Clearing the Windows DNS Server cache from the command line is an easy task.

    C:\> dnscmd . /clearcache

    The . indicates the local DNS server. You can use this command to clear the cache of remote DNS servers by replacing the . with the hostname or IP address of the remote server.



      [Read more...]
    Don’t forget to monitor your nameservers
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    As I mentioned in a past article I got my IPv6 connectivity working so started working on setting up various IPv6 services. One of these was to setup my name server so it also worked on IPv6. This worked fine, but recently I lost my IPv6 connectivity but thought no more about it. I’m trying [...]
    Tech Messages | 2010-05-14
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    A special extended edition of Tech Messages for 2010-04-29 through 2010-05-14:

      [Read more...]
    MySQL – IP vs DNS
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    A MySQL is running happily on a machine situated in a land far far away. I grant access to a user@machine_aaaaaa (grant select on db.* to ‘user’@'machine_aaaaa’ identified by ‘password’; flush privileges;), send an email to the user saying it should run fine and happily go off my way. Mistake!

    It seems this user can’t connect to the mysql gets access denied:
    Access denied for user ‘user’@'machine_bbbbb’ (using password: YES)

    Note that the machine the user is being seen from is totally different from the one I set up in the grant!! WHY?

    run a reverse lookup on the ip of machine_aaaaa, turns out it shows machine_bbbbb. So I figure a big bad guy messed up /etc/hosts, I was right! `cat /etc/hosts` just to find an entry for machine_aaaaa blehh

    Ok, solution is to remove the entry from /etc/hosts (after


      [Read more...]
    NoSQL vs MySQL
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    No I did NOT post the following comment

    This is ridiculous. You didn't test MySQL, you tested a failing DNS lookup on authentication.

    resulting in the follow up post :


    My previous post Redis, Memcache, Tokyp Tyrant, MySQL comparison had a flaw as pointed out by this comment. The MySQL was taking a huge time for doing a reverse DNS lookup.

    But as always ... Everything is just a Freaking dns problem :)

    Technorati Tags: dns dnsproblem



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    Four short links: 5 October 2009
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  • Brown Cloud Marketing -- advertorial "interviewing" GM of a company offering "DNS in the cloud". This might be a worthwhile service, but the way he markets it (by saying open source is "freeware" and the market leader is "legacy") reveals a rich vein of bozo. Freeware legacy DNS is the internet's dirty little secret (actually, it's the reason we have a functioning DNS), Nominum software was written 100 percent from the ground up, and by having software with source code that is not open for everybody to look at, it is inherently more secure. (security through obscurity is equating clothing with being naked yet blind). The Internet kindly did the poor man's homework:
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    The Story Repeats
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    I covered this one before .. but as it struck twiced today .. I think it's worth repeating. Both my collegue Karl and Trent ran into the same problem , within hours hours of eachother, a missing or failing reverse dns mapping that caused performance issues .. and a lot of log entries..

    Karl denies having a second life in Perth but I`m not really sure about that ...

    But I guess they both have to agree... Everything is a fscking DNS problem.
    (I noticed other people using that spelling this weekend, on stage in the Janson)

    Technorati Tags: dns
      [Read more...]
    Installing PowerDNS (With MySQL Backend) And Poweradmin On CentOS 5.2
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    Installing PowerDNS (With MySQL Backend) And Poweradmin On CentOS 5.2

    This article shows how you can install the PowerDNS nameserver (with MySQL backend) and the Poweradmin control panel for PowerDNS on a CentOS 5.2 system. PowerDNS is a high-performance, authoritative-only nameserver - in the setup described here it will read the DNS records from a MySQL database (similar to MyDNS), although other backends such as PostgreSQL are supported as well. Poweradmin is a web-based control panel for PowerDNS.

    Installing PowerDNS (With MySQL Backend) And Poweradmin On Debian Etch
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    Installing PowerDNS (With MySQL Backend) And Poweradmin On Debian Etch

    This article shows how you can install the PowerDNS nameserver (with MySQL backend) and the Poweradmin control panel for PowerDNS on a Debian Etch system. PowerDNS is a high-performance, authoritative-only nameserver - in the setup described here it will read the DNS records from a MySQL database (similar to MyDNS), although other backends such as PostgreSQL are supported as well. Poweradmin is a web-based control panel for PowerDNS.

    MySQL and DNS woes?
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    A quick solution to a common problem: your MySQL server has thousands of connections, some or most are not persistent. Unless you say otherwise, MySQL will check connections hostnames against the system DNS server. While this is generally not a problem with low traffic, when you are dealing with many concurrent connections you are not only wasting cycles with DNS name resolve, you may also overwhelm or alert your DNS server/provider. The solution? Set skip-name-resolve in the my.cnf file and MySQL will run the connections off of their IP address instead of the DNS name that it resolves to.  

    What is an “unauthenticated user”?
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    Every so often we have a client worrying about unauthenticated users. For example, as part of the output of SHOW PROCESSLIST they will see:

    +-----+----------------------+--------------------+------+---------+------+-------+------------------+
    | Id  | User                 | Host               | db   | Command | Time | State | Info             |
    +-----+----------------------+--------------------+------+---------+------+-------+------------------+
    | 235 | unauthenticated user | 10.10.2.74:53216   | NULL | Connect | NULL | login | NULL             |
    | 236 | unauthenticated user | 10.120.61.10:51721 | NULL | Connect | NULL | login | NULL             |
    | 237 | user                 | localhost          | NULL | Query   | 0    | NULL  | show processlist |
    +-----+----------------------+--------------------+------+---------+------+-------+------------------+
    
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    Virtual Hosting Howto With Virtualmin On CentOS 5.1
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    Virtual Hosting Howto With Virtualmin On CentOS 5.1

    This tutorial shows how to set up a CentOS 5.x server to offer all services needed by virtual web hosters. These include web hosting, smtp server with (SMTP-AUTH and TLS, SPF, DKIM, Domainkeys), DNS, FTP, MySQL, POP3/IMAP, Firewall, Webalizer for stats.

    Virtual Hosting Howto With Virtualmin On CentOS 5.1
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    Virtual Hosting Howto With Virtualmin On CentOS 5.1

    This tutorial shows how to set up a CentOS 5.x server to offer all services needed by virtual web hosters. These include web hosting, smtp server with (SMTP-AUTH and TLS, SPF, DKIM, Domainkeys), DNS, FTP, MySQL, POP3/IMAP, Firewall, Webalizer for stats.

    Trick or Treat - Web 2.0 Goodies for ColdFusion
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    I am happy to announce the latest creation from foundeo: fusionKit.

    fusionKit is a CD full of some handy ColdFusion components and UDF's. It is a similar concept to the DRK's that Macromedia used to sell, but is it's 100% ColdFusion.

    My favorite component in the kit is the Bayesian CFC. You may recall that spam filters tend to use bayesian analysis to determine if a message is spam or ham. This CFC allows you to perform the same kind of analysis on any block of text. I am using this CFC in one of my client's blogs, and it has blocked over 4,000 spam comments in one week!

    There is also the tagging CFC, which

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    PowerDNS
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    Ooooh... a dns system that gets its info from a database. Now all I need is a DHCP daemon that will talk to the same database. Then my domain name system will be as cool as Active Directory :)

    http://wiki.powerdns.com/projects/trac/
    PowerDNS
    +0 Vote Up -0Vote Down
    Ooooh... a dns system that gets its info from a database. Now all I need is a DHCP daemon that will talk to the same database. Then my domain name system will be as cool as Active Directory :)

    http://wiki.powerdns.com/projects/trac/
    Showing entries 1 to 21

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