Archive for January, 2012

VMware NIC Types and Characteristics

January 30th, 2012 No comments

Available Network Adapters
Only those network adapters that are appropriate for the virtual machine you are creating are available configuration options in the Choose Networks window. Read more…

Categories: VMWare Tags:

Using TCPDUMP to Filter on DSCP

January 29th, 2012 No comments

The TCPDUMP filter to match a DSCP is a little tricky to construct. I need to explain how the filter works and also what TCPDUMP sees in the ToS Byte of the IP header and then how to filter on just the DiffServ extensions.

The IP ToS Byte (DSCP and IP ECN)

The IP ToS Byte (DSCP and IP ECN)

(in case it is not important to understand how the filter is constructed)

an example filtering on DSCP decimal 20 (AF22):
tcpdump -i eth0 (ip and (ip[1] & 0xfc) >> 2 == 20) -vvv

An example filtering on DSCP Hex 14 (also decimal 20 or AF22):
tcpdump -i eth0 (ip and (ip[1] & 0xfc) >> 2 == 0x14) –vvv
Read more…

Categories: Protocol Analysis, QoS Tags: , ,

The Story of Linux

January 23rd, 2012 No comments

A video from The Linux Foundation, commemorating 20 Years of the Linux Operating System: Read more…

Categories: linux Tags:

Configuring Elastix SIP Trunk to Sipgate

January 16th, 2012 No comments

Another aide-memoir, these are the setting required to enable a sipgate account (and PSTN number) to connect to a phone registered to your Elastix / Asterisk PBX:
Read more…

Categories: Voice over IP Tags: ,