Encryption failure: Received a cleartext packet within an encrypted connection

Recently I've stumbled upon a strange looking site-to-site (CheckPoint R70 to Cisco VPN3k) VPN problem:

Connections from some networks were dropped with the following error:

Encryption failure: Received a cleartext packet within an encrypted connection

The first step was to check the encryption domains for the tunnel. In both GUI and /etc/fw/conf/user.def the encryption domain was the whole class B network, assigned to the company.

Next step was tracing.

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How to serve attachments from a free CDN (Coral)

You can use Coral free CDN to off-load the WordPress attachments (usually images). In order to use Coral you need to add ".nyud.net" to the site DNS address. For example, http://www.alekz.net will become http://www.alekz.net.nyud.net. Coral is usually too slow to serve all static content, so the most effective solution would be to use it only for the biggest files.

Here's a simple solution. Add the following to functions.php of your current theme:

add_filter ('wp_get_attachment_url', 'freecdn_url');

function freecdn_url ($url)
    if (! is_attachment () ) return $url; 
    $cdn_url = ".nyud.net";
    $decomposed_url = explode ("/", $url);
    $decomposed_url[2] =  $decomposed_url[2] . $cdn_url;
    $url = implode("/", $decomposed_url);
    return $url;

Your theme (e.g. the bundled "TwentyTen") must use wp_get_attachment_url(), of course. If not – you got the idea, didn't you? ;-)

Also, you can use freecdn_url () function to rewrite any URL you want to download from Coral.

Useful firefox settings

The default settings are in bold.

  • media.autoplay.enabled (true|false)
  • image.animation_mode (normal|once|none)
  • security.enable_java (true|false)
  • browser.sessionstore.interval (10000 in msecs, equivalent to 10secs)
  • gfx.color_management.enabled (true|false)
  • browser.tabs.closeButtons 1 ( 0 – on the active tab only, 1- all tabs, 2- no close button, 3- at the end of the tab strip)
  • dom.max_script_run_time (10 sec)
  • layout.spellcheckDefault (0 – disable the spell checker, 1 – spell checker for multi-lines text boxes only, 2 – enable the spell checker for all text boxes)
  • network.http.pipelining (true|false)
  • network.http.proxy.pipelining (true|false)
  • network.http.pipelining.maxrequests (4, 4-8)
  • network.http.max-connections (30)
  • network.http.max-connections-per-server (15)
  • extensions.checkCompatibility ( New -> Boolean)
  • security.dialog_enable_delay (2000 in msec, 0 – start installation immediately)
  • nglayout.initialpaint.delay (New -> Integer)
  • browser.blink_allowed (true|false)
  • middlemouse.paste (true|false)
  • ui.submenuDelay (New -> Integer)
  • network.prefetch-next (true|false)
  • browser. cache.check_doc_frequency (0 – check once per browser session, 1 – Check every time I view the page, 2 – Never check (always use cached page), 3 – Check when the page is out of date)