Networking Tips Tricks

Integrating Active Directory into Open Directory is now so easy you could probably do it with blink of your eyes (well, that may be a exaggerated statement, but you could probably do it in under 5 minutes). 10.4  & older MAC releases Active Directory integration was horrific most of the time. The last 10.4.11 server that I tried to join to Active Directory (just join, not even integrate) failed to login ever again.  I’m sure that I could have troubleshooted the problem and fixed it, but it was easier for me to just upgrade the server to 10.5.

What is a WEP Key? Wired Equivalent Privacy  ( WEP ) is a weak security algorithm for IEEE 802.11 wireless networks. Introduced as part of the original 802.11 standard ratified in September 1999, its intention was to provide data confidentiality comparable to that of a traditional wired network. WEP, recognizable by the key of 10 or 26 hexadecimal digits, is widely in use and is often the first security choice presented to users by router configuration tools. Although its name implies that it is as secure as a wired connection, WEP has been demonstrated to have numerous flaws and has been deprecated in favor of newer standards such as WPA2. In 2003 the Wi-Fi Alliance announced that WEP had been superseded by Wi-Fi Protected Access (WPA). In 2004, with the ratification of the full 802.11i standard (i.e. WPA2), the IEEE declared that both WEP-40 and WEP-104 "have been deprecated as they fail to meet the...

Packet crafting is a technique that allows network administrators or hackers to probe firewall rule-sets and find entry points into a targeted system or network. This is done by manually generating packets to test network devices and behaviour, instead of using existing network traffic. Testing may target the firewall, IDS, TCP/IP stack, router or any other component of the network. Packets are usually created by using a packet generator or packet analyzer which allows for specific options and flags to be set on the created packets. The act of packet crafting can be broken into four stages: Packet Assembly, Packet Editing, Packet Play and Packet Decoding. Tools exist for each of the stages - some tools are focussed only on one stage while others such as Ostinato try to encompass all stages .

Password cracking  is the process of recovering passwords from data that has been stored in or transmitted by a computer system. A common approach is to repeatedly try guesses for the password. The purpose of password cracking might be to help a user recover a forgotten password (though installing an entirely new password is less of a security risk, but involves system administration privileges), to gain unauthorized access to a system, or as a preventive measure by system administrators to check for easily crackable passwords. On a file-by-file basis, password cracking is utilized to gain access to digital evidence for which a judge has allowed access but the particular file's access is restricted.

Definition:  Automatic Private Internet Protocol Addressing (APIPA) is a common alternative to the use of the Dynamic Host Configuration Protocol (DHCP) to request and retrieve an Internet Protocol (IP) address for a host. APIPA simplifies the assignment of IP address and subnet-mask configuration information to hosts in small networks. When APIPA is used, the operating system allows the assignment of a unique IP address to each station on a small local area network (LAN). This avoids the administrative overhead of running a DHCP server or manually setting IP configuration information. APIPA is a procedure and set of guidelines for performing these configuration functions, not an actual protocol. It first appeared on the Windows platform in Windows 2000.

RIP v1 RIP v2 IGRP EIGRP OSPF IS-IS BGP Interior/Exterior? Interior Interior Interior Interior Interior Interior Exterior Type Distance Vector Distance Vector Distance Vector Hybrid Link-state Link-state Path Vector Default Metric Hopcount Hopcount Bandwidth/Delay Bandwidth/Delay Cost Cost Multiple Attributes Administrative Distance 120 120 100 90 (internal) 110 115 20 (external) 170 (external) 200 (internal) Hopcount Limit 15 15 255 (100 default) 224 (100 default) None None EBGP Neighbors: 1 (default) IBGP Neighbors: None Convergence Slow Slow Slow Very Fast Fast Fast Average Update timers 3...

The Rapid Spanning Tree Protocol (RSTP) is an optimized version of STP. RSTP allows a newly elected root port or designated port to enter the forwarding state much quicker under certain conditions than in STP, hence quicker network convergence. Although RSTP allows quicker network convergence, it has the same drawback as STP does: All bridges within a LAN share the same spanning tree, so redundant links cannot be blocked based on VLAN and the packets of all VLANs are forwarded along the same spanning tree. Network Diagram Figure 1  Network diagram for RSTP configuration

Multiple Spanning Tree Protocol (MSTP) supports mapping multiple VLANs to one multiple spanning tree instance (MSTI) by means of a VLAN-to-MSTI mapping table. It allows data flows of VLANs to be forwarded along separate paths as defined in the mapping table, thus reducing communication overheads and resource usage. Note that one VLAN cannot map to multiple MSTIs. Network Diagram Figure 1-1  Network diagram for MSTP configuration