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27 Cards in this Set
- Front
- Back
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OSI Layer 1 |
Physical Transmission (electric signals, etc.) |
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OSI Layer 2 |
Data Link MAC Layer - error connection, switches (node to node transmission) |
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OSI Layer 3 |
Network Layer - Subnets, icmp, routers/firewalls |
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OSI Layer 4 |
Transport Layer - Ensures delivery of entire file/msg, TCP, UDP |
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OSI Layer 5 |
Session Layer - Start, stops session, maintains order |
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OSI Layer 6 |
Presentation Layer - Encryption, conversion from ASCII to EBCDIC, BCD to Binary, SSL, MIME |
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OSI Layer 7 |
Application Layer - "Communication" Email, file transfer, client server Smtp, HTTP, FTP |
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Network Devices - Hub |
10 MB/Half Duplex Transmissions Takes in data, repeats to all ports Useful for "mirroring, capturing." |
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Network Devices - Switch |
10/100/1000 Full Duplex Transmissions Eliminates bandwidth sharing, congestion Sends traffic to only one port by maintaining MAC through port mapping |
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Network Devices - Gateway/Router |
Connects at least 2 networks together, to switch data between them Provide NAT translation if needed May contain a firewall |
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Network Devices - Proxy |
Device filters, redirects, blocks traffic per policy Caches for faster data access Provides lan client IP masking |
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Linux Collision troubleshooting |
collisions:5662548 txqueuelen:1000 |
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Linux speed of transmissions |
[root@10.4.138.249] # mii-tool eth0: negotiated 100baseTx-FD flow-control, link ok |
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Linux Duplex |
[root@10.4.138.249] # mii-tool eth0: negotiated 100baseTx-FD flow-control, link ok |
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Full Duplex vs. Half Duplex |
Refers to the transmission of data in two directions simultaneously. For example, a telephone is a full-duplex device because both parties can talk at once. In contrast, a walkie-talkie is a half-duplex device because only one party can transmit at a time. |
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Address Resolution Protocol (ARP) |
Translation between a device's hardware address (MAC) layer 2 and its network address (IP) layer 3 Only operates within same subnet LAN segments Switching devices, nodes keep ‘arp table’ which stores mac, ip, port of switch informationWorkstation needs address for 10.10.10.5 Sends a broadcast to 10.10.10.255, broadcast returns information from ARP table with MAC mapping to 10.10.10.5[root@216.101.241.120] # arp -a ? (216.101.241.1) at 00:01:96:ce:98:80 [ether] on eth0 |
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Internet Protocol (IP) addressing |
Used to uniquely identify a node/network on the internet |
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Private IP Addresses |
Class A I 10.0.0.1 - 10.255.255.255 B I 172.16.0.0 - 172.31.255.255 C I 192.168.0.0 - 192.168.255.255 |
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IPv4 |
Format: 208.47.125.33 Separated by subnets |
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Private/NAT IP ranges |
Used for small private networks using Network Address Translation (routers/gateway) |
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IPv6 |
Meant to cope with issue of running out of IPv4 addressing (around 2011) Not support by barracuda yet Format: 2001:db8:0:1234:0:567:1:1 |
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Subnetting |
Introduced to allow a single larger network to have a number of smaller networks within it Range of logical addresses within the address space assigned to an organization. The addresses of all nodes in a subnet start with the same binary sequence, which is the subnet's network ID and subnet ID |
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Network Address Translation (NAT) |
Network address translation (NAT, also known as network masquerading, native address translation or IP masquerading) is a technique of transcribing network traffic through a router that involves rewriting the source and/or destination IP addresses and usually also the TCP/UDP port numbers of IP packets as they pass through. |
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TCP |
TCP (Transmission Control Protocol) is the most commonly used protocol on the Internet. Connection State protocol:Acknowledgement sequence Error Correction Flow Control (resending)Example: FTP,HTTP,SMTP |
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UDP |
UDP (User Datagram Protocol) Connectionless ProtocolUsed for faster, non critical data with no error checking.EXAMPLE: VOIP, Gaming, DNS, NTP |
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TCP 3 way handshake |
Client sends server (SYN) request Server receives client (SYN) Server sends Client (SYN) request Client receives server (SYN) Client sends Acknowledgement (ACK) to serverServer receives Acknowledgement (ACK) |
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TCP Flags: |
SYN (Synchronize) ACK (Acknowledgement Push (Push ack) RST (Reset connection) FIN (Final Sequence) |
