Tag Archives: net_dns2

Net_DNS2 v1.4.3 – Interim Bugfix Release

I’ve released version 1.4.3 of the PEAR Net_DNS2 library- this release is primarily just bug fixes.

You can install it now through the command line PEAR installer:

pear install Net_DNS2

Or, you can also add it to your project using composer:

composer require pear/net_dns2

Version 1.4.3

  • fixed an issue when looking up . or com., when using the strict_query_mode flag.
  • fixed a bug in the caching logic where I was loading the content more than once per instance, when really I only need to do it once.
  • changed the Net_DNS2::sock array to use the SOCK_DGRAM and SOCK_STREAM defines, rather than the strings ‘tcp’ or ‘udp’.
  • fixed a bug in the Net_DNS2_Header and Net_DNS2_Question classes, where I was using the wrong bit-shift operators when parsing some of the values. This only became apparent when somebody was trying to use the CAA class (id 257); it was causing this to roll over to the next 8 bit value, and returning 1 (RR A) instead of the CAA class.
  • fixed a bug that occurs when a DNS lookup request times out, and then the same class is reused for a subsequent request. Because I’m caching the sockets, the timed out data could eventually come in, and end up being seen as the result for a subsequent lookup.
  • fixed a couple cases in NSAP.php where I was comparing a string to an integer.

Net_DNS2 v1.4.2 – SMIMEA and AVC Resource Records and SHA-256 SSHFP

I’ve released version 1.4.2 of the PEAR Net_DNS2 library- you can install it now through the command line PEAR installer:

pear install Net_DNS2

Or, you can also add it to your project using composer:

composer require pear/net_dns2

Version 1.4.2

  • changed the role for the README.md file to doc.
  • parse the resolv.conf options line; right now I just support the timeout and rotate options.
  • the options values only work if you set the new option use_resolv_options to true; this is to keep backwards compatibility.
  • added support for RFC 6594; support for SHA-256 and ECDSA in the SSHFP resource record.
  • added the SMIMEA resource record; this just extends the TLSA record.
  • added the AVC resource records; this just extends the TXT record.
  • added error and EDNS0 defines for DNS Cookies (RFC7873).
  • added EDNS0 defines to the lookup class.
  • dropped the Net_DNS2_Packet::formatIPv6() function; this was deprecated in v1.1.3.
  • re-wrote the Net_DNS2::expandIPv6() function. Based on testing, the new version is about twice as fast.

Net_DNS2 Moved to GitHub

I’ve never been a bit fan of git- I’ve got used to using SVN over the years, and never saw a compelling reason to change- until now- that Google is shutting down the Google Code service- so I’m forced to move.

Luckily I can still keep using SVN with GitHub- I can put off actually using git for the foreseeable future!

The new Net_DNS2 repository is officially moved to GitHub:

https://github.com/mikepultz/netdns2

DNS in PHP: How to Use the Net_DNS2 Library

The PEAR Net_DNS2 DNS resolver library has been around for a while now- I originally wrote it in late 2010, with the latest release just a few months ago.

Net_DNS2, much like its predecessor Net_DNS, is a native DNS resolver/updater- which means it does not use system commands and is not a language binding on top of a C library, but instead, uses UDP/TCP sockets to communicate directly with DNS servers to retrieve the requested information.

Net_DNS2 will use the name servers specified in your resolv.conf file (for *nix users), or you can specify which name severs to use directly in the config.

Simple Lookup Example

This example uses the Google public DNS servers, to look up the A records for google.com:

$r = new Net_DNS2_Resolver(array('nameservers' => array('8.8.8.8')));    

try
{
    $result = $r->query('google.com', 'A');     

    foreach($result->answer as $record)
    {
        echo $record->address, "\n";
    }

} catch(Net_DNS2_Exception $e)  
{
    echo "::query() failed: ", $e->getMessage(), "\n";    
}

The result is:

66.185.85.45
66.185.85.34
66.185.85.59
66.185.85.30
66.185.85.54
66.185.85.35
66.185.85.39
66.185.85.55
66.185.85.49
66.185.85.25
66.185.85.40
66.185.85.24
66.185.85.44
66.185.85.29
66.185.85.20
66.185.85.50

Net_DNS2 currently supports 58 different resource record types, including all the resource records required for DNSSEC, and some resource records that have only been defined a few months ago, like the OPENPGPKEY record.

Here is an example looking up the MX records (for mail delivery) for gmail.com:

$r = new Net_DNS2_Resolver(array('nameservers' => array('8.8.8.8')));
try
{
    $result = $r->query('gmail.com', 'MX');

    foreach($result->answer as $record)
    {
        printf("preference=%2d, host=%s\n", $record->preference, $record->exchange);
    }

} catch(Net_DNS2_Exception $e)
{
    echo "::query() failed: ", $e->getMessage(), "\n";
}

The result is:

preference=40, host=alt4.gmail-smtp-in.l.google.com
preference=20, host=alt2.gmail-smtp-in.l.google.com
preference= 5, host=gmail-smtp-in.l.google.com
preference=30, host=alt3.gmail-smtp-in.l.google.com
preference=10, host=alt1.gmail-smtp-in.l.google.com

Simple Update Example

Net_DNS2 can also be used to make dynamic DNS updates. This example updates the MX record for the domain “example.com”. For updates, the DNS server you want to specify is the authoritative DNS server for the domain, and not simply a resolver:

$u = new Net_DNS2_Updater('example.com', array('nameservers' => array('192.168.0.1')));

try  
{
    //    
    // create a new MX RR object to add to the example.com zone    
    //    
    $mx = Net_DNS2_RR::fromString('example.com MX 10 mail.google.com');         

    //    
    // add the record    
    //    
    $u->add($mx);    

    //    
    // add a TSIG RR to authenticate the request 
    //    
    $u->signTSIG('my-key', '9dnf93asdf39fs');    

    //    
    // execute the request    
    //    
    $u->update();    

} catch(Net_DNS2_Exception $e)  
{
        echo "::update() failed: ", $e->getMessage(), "\n";
}

Net_DNS2 supports authentication via TSIG or SIG(0) (current supports RSA keys only); this is often required for sending DNS updates (as in the example above), or for making full zone-transfer requests, like this:

$r = new Net_DNS2_Resolver(array('nameservers' => array('8.8.8.8')));

//
// sign with TSIG to authenticate the zone transfer
//
$r->signTSIG('mykey', '9dnf93asdf39fs');

try
{
    $result = $r->query('example.com', 'AXFR');

    foreach($result->answer as $record)
    {
        echo $record;
    }

} catch(Net_DNS2_Exception $e)
{
    echo "::query() failed: ", $e->getMessage(), "\n";
}

Net_DNS2 is available as a PEAR module, or via Packagist; you can also find out more on the Net_DNS2 website.