Archive for August, 2012

OpenSSL – Generate CSR and Test Signed x.509 Certificate

August 28th, 2012 No comments

Another personal aide-memoir for SSL testing:
This method uses OpenSSL to create public/private keys pair and submit the public key to a Certificate Signing Authority to be signed by that CA. The procedure uses various methods to test certificates and SSL connections to web servers: Read more…

Categories: Security Tags: ,

HTTP Cache Control and the ETag

August 16th, 2012 No comments

HTTP and ETag

Download this capture file:IfModifieldSince_and_ETag

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With caching enabled, a web server does not need to send a full response if content has not changed.

  • If-Modified-Since is an HTTP request header that the client sends to your browser along with a request for content.
  • Last-Modified is an HTTP response header that the server returns along with the requested content.

If-Modified-Since Allows a 304 Not Modified to be returned if content is unchanged
If-Modified-Since: Sat, 29 Oct 1994 19:43:31 GMT

If-None-Match Allows a 304 Not Modified to be returned if content is unchanged,
If-None-Match: "737060cd8c082f209582d" Read more…

Categories: Protocol Analysis Tags: ,

SIP – Example Simple Two-Party Call Flow

August 14th, 2012 No comments


Download this capture file:SIP – RTCP control through NAT Device

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SIP is defined by RFC 2543 and is used for multimedia call session setup and control over IP networks. Read more…

Categories: Voice over IP Tags: ,

Path MTU Discovery (PMTU)

August 13th, 2012 No comments

An aide-memoir for PMTU operation.
Usually, the path MTU is determined using MTU Path Discovery. Usually, two hosts can dynamically negotiate the path MTU (e.g. client and server ) but networks that contain firewalls or tunnels (VPN, GRE, IPSec transport mode) sometimes require tuning the MTU values manually. Read more…

Categories: Uncategorized Tags: