Networking

• when data exists and can collide if going in
• different directions

Physical Address of a NIC

• 48 bits notated in hexadecimal. The first 24 characters are used to identify the
• manufacturer. The second 24 characters are a unique identifier.

• Address Resolution Protocol, is used to
• identify MAC Address

• TCP
• is a reliable three way handshake of synchronize/synchronize
• acknowledge/acknowledge to guarantee delivery.

• UDP
• is unreliable, but faster

• Network
• Address

• Broadcast
• Address

• Subnet
• Mast

• Range
• of valid IPs

• Number
• of hosts

Classless Inter Domain Routing

• 1. Check to see if the destination is on the connected network
• 2. Select a gateway to send the packet to
• 3. ARPs for selected gateway to get the MAC address
• 4. Sends the packet to the resolved gateway

When a data packet is continually routed through the same routers over and over. The data packets continue to be routed within the network in an endless circle.

A network route that goes nowhere. It is pointing an address space to an invalid destination

Virtual LAN that exists on top of existing architecture, often with other physical hardware

A switch port setting that does not strip the VLAN tags on outgoing packets, (Allows multiple switches to work on the same VLAN)

Private IP addresses

10.0.0.0/8

172.16.0.0/12

192.168.0.0/16

• 127.0.0.0/8
• - used for loopback

• 169.254.0.0/16
• - used for communication between hosts on a single link. Hosts obtain these
• addresses by auto-configure, such as when a DHCP server may not be found and a
• static IP address has not been configured. Also known as APIPA (Automatic
• Private IP Addressing).

Network Address Translation

A method of modifying a private IP address so that it appears as a public IP address.

Dynamic Host Configuration Protocol.

• Allows the automatic assignment of a dynamic IP address to a host within a defined scope of a given network.
• (Rackspace does not deploy DHCP to any of its customers)

Transport Offload Engine

• Allows some or all of the processing of incoming networks packets to be processed by the NIC.
• (Rackspace's default is to turn this off)

Public Net: Rackspace public network that everyone can see

Private Net: Customer specific private network

Service Net: Rackspace service network

DRACNET: allows DRAC access

ExNet: Rackspace cabinet network interface

Maximum of 4,096 VLANs.

DCs are setup in zones and each zone has it's own set of VLANs.

the method used to bridge two or more switches in different cabinets over the same VLAN

A device that repeats a signal to extend the 300' limit of network cable

A switch that functions on layer 2 & 3. It has the ability to do routing and perform on both layers.

Intrusion Detection Device

• A device that monitors network traffic. It can
• identify anomalous packet content or patterns of traffic that are different from normal for any particular network. Identify patterns, called signatures, of malicious content within packets coming into or leaving a network. Identify changes in the security health or "state of a server.

IDS is managed by Alert Logic for Rackspace

Web Application Firewall

An appliance, server plugin, or filter that applies a set of rules to an HTTP conversation

The time given to the dynamic IP before it expires

People Don't Need Those Stupid Packets Anyway

• 7) Application Layer (IE, HTML)
• 6) Presentation Layer (OS)
• 5) Session Layer (HTTP, FTP), SMTP)
• 4) Transport Layer (TCP,UDP) ICMP is a multi-layer Protocol on both layer 3 & 4
• 3) Network Layer  (IP,addresses,routes,subnets)
• 2) Data Link Layer (MAC Address layer-should be a unique ID found using ARP|LLC Logical Link Layer)
• 1) Physical Layer (Cables, repeater, hub, NIC)