Modern processors can only handle one instruction from one program at any given point in time. Each instruction that is sent to the processor is called a thread. Even though it seems as if you’re multitasking with your computer (running more then one program at a time) you’re really not . Read more…
Normal TCP options are Type 0 (End of Option List), 1 (No-Operation), 2 (Maximum Segment Size, len 4), 3 (WSOPT – Window Scale, len 3), 4 (SACK Permitted, len 2), 5 (SACK, len N), and 8 (TSOPT – Time Stamp Option, len 10). Read more…
IEEE 802.11n uses the multiple-input-multiple-output (MIMO) technology that enables spatial signal diversity and spatial signal multiplexing enabling increased range and data transmission rates. 802.11n allows use of wider 40 MHz channels to double the bandwidth as compared to the legacy 20 MHz operation.
AirPcap NX adaptors can be configured to capture data on 40MHz channels but you will need to determine the “extension channel” Read more…
Simple and Protected GSSAPI Negotiation Mechanism (SPNEGO)
1. A client requests (HTTP GET) a page from a server;
2. The server returns HTTP code 401 along with a header: “WWW-Authenticate: Negotiate” (Authentication Required, and we can negotiate);
3. The client the re-sends the request (HTTP GET) but this time with an authorisation header (“Authorization: Negotiate “) along with three “MechTypes” (for example MS Kerberos 5, Kerberos 5 and NTLMSSP);
4. The server authenticates the client using one of the MechTypes (for example “supportedMech” used may be for an IIS server MS Kerberos 5), returning an HTTP 200 (OK) along with the last authenticate header plus the data requested.
Pointer Record (PTR)
Pointer records are the opposite of A and AAAA RRs and are used in Reverse Map zone files to map an IP address (IPv4 or IPv6) to a host name. Read more…
IPv4 IN-ADDR.ARPA Reverse Mapping Domain
We defined the normal domain name structure as a tree starting from the root. We write a normal domain name LEFT to RIGHT but the hierarchical structure is RIGHT to LEFT.
domain name = www.example.com Read more…
highest node in tree is = .com
next (lower) = .example
next (lower) = www
The Open Source Xen hypervisor runs directly on the hardware and becomes the interface for all hardware requests such as CPU, I/O, and disk for the guest operating systems. By separating the guests from the hardware, the Xen hypervisor is able to run multiple operating systems securely and independently. Read more…
At a recent Riverbed Technology event in Denver, Colorado, Steve McCanne, Loris Degioanni, and Gerald Combs shared the stage and told the story of the history behind their inventions TCPDUMP, WinPcap, and Wireshark. To view the video: Read more…
Reproduced for the benefit of others who are attempting to get this USB Wireless LAN adaptor working on CentOS. The Edimax EW-7318 uses the RealTek chipset.
Ralink RT2500 series chipsets are supported by the rt73usb/rt2500usb kernel drivers. A typical supported device is the Belkin Wireless G USB Network Adapter (RT2571F chipset). This device requires the rt73usb firmware which is currently available from http://elrepo.org Read more…
Another aide-memoir reproduced from voip-info.org: Asterisk provides Voicemail services with Directory, Call Conferencing, Interactive Voice Response, Call Queuing. It has support for three-way calling, caller ID services, ADSI, IAX, SIP, H.323 (as both client and gateway), MGCP (call manager only) and SCCP/Skinny. SEE ALSO: The Asterisk Book
