Computer and Network Reference

The following information is provided as a free informational service on a variety of Information Technology subjects.  Click on the subject heading below to expand list of subject matter.

Start a continuous PING command

Start->Run->CMD->enter
ping 192.168.1.254 –t   (ping xxx.xxx.xxx.xxx  -t)

 


Comparison of the OSI and DOD models

DOD Model OSI Model   Network Protocols
Process / Application Application Telnet, FTP, SMTP, FTAM (File Transfer, Access, and Management), VTP (Virtual Terminal Protocol),CMID (Common Management and Information Protocol
Presentation ASCII, EBCDIC, JPEG, GIF, TIFF, MPEG, WAV
Session RPC, ZIP (Zone Information Protocol), SCP (Session Control Protocol)
Host to Host Transport TCP, UDP, SPX, NBP (Name Binding Protocol)
Internet Network IP, ICMP, IGRP, IPv6, GRE, IPX in IP, L2TP, ARP, RARP, Ping, Tracert, IPX, BGP, OSPF, RIP
Network Access Datalink Logical Link Control (LLC)Layer LAN – Ethernet (802.3), Fast Ethernet, Token Ring (802.5), Wi-Fi (802.11), FDDI
WAN -Frame Relay, ATM, LAP, LAPB (Link Access Procedure, Balanced), SDLC(Synchronous Data Link Control), PPP, SMDS, SIP
Media Access Control (MAC) Layer MAC (hardware) addressing
Physical Electrical (Copper), Optical (Fiber), Radio (Air), Photonic (Light, Laser)

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Memory Chart

Type Speed Bus Speed
DDR PC2100 266Mhz 133MHz
DDR PC2700 333MHz 166MHz
DDR PC3200 400MHz 200MHz
DDR PC3500 433MHz 216MHz
DDR PC3700 466MHz 233MHz
DDR PC4000 500MHz 250MHz
DDR PC4200 533MHz 266MHz
DDR PC4400 550MHz 275MHz
DDR PC4500 566MHz 283MHz
DDR PC4800 600MHz 300MHz
DDR PC5000 625MHz 313MHz
DDR2 PC2-4200 533MHz 266MHz
DDR2 PC2-5400 667MHz 333MHz
DDR2 PC2-6000 750MHz 375MHz
DDR2 PC2-6400 800MHz 400MHz
DDR2 PC2-8000 1000MHz 500MHz
DDR2 PC2-8800 1100MHz 550MHz
DDR2 PC2-9000 1120MHz 560MHz
DDR3 PC3-6400 800MHz 400MHz
DDR3 PC3-8500 1066MHz 533MHz
DDR3 PC3-10666 1333MHz 667MHz
DDR3 PC3-12800 1600MHz 800MHz
DDR3 PC3-14400 1800MHz 900MHz
DDR3 PC3-16000 2000MHz 1000MHz

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IEEE 802 Working Groups and Networking Protocols

Standard Name Description Status
802.1 Higher Layer LAN Protocols Working Group Active
802.2 Novell Logical Link Control Working Group Inactive
802.3 Ethernet Ethernet Working Group Active
802.4 Token Bus Working Group Inactive
802.5 Token Ring Token Ring Working Group Inactive
802.6 Metropolitan Area Network Working Group Disbanded
802.7 Broadband TAG Disbanded
802.8 Fiber Optic TAG Disbanded
802.9 Isochronous LAN Working Group Inactive
802.10 Security Working Group Inactive
802.11 Wi-Fi Wireless LAN Working Group Active
802.12 Demand Priority Working Group Inactive
802.14 Cable Modem Working Group (Temporarily housed off-site) Disbanded
802.15 Wireless Personal Area Network (WPAN) Working Group Active
802.16 Broadband Wireless Access Working Group Active
802.17 Resilient Packet Ring Working Group Active
802.18 Radio Regulatory TAG Active
802.19 Coexistence TAG Active
802.20 Mobile Broadband Wireless Access (MBWA) Working Group Active

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Windows Name Resolution

WINS NETBIOS
Local NetBIOS Name Cache Local Host Name
WINS Server HOSTS Files
B-Node Broadcast DNS
LMHOSTS File

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Windows Small Business Server 2003 Port Forwarding

For full functionality of SBS 2003 (SBS2003) Remote Web Workplace, forward the following ports at your router or firewall:

SMTP 25 – Simple Mail Transfer Protocol

HTTP 80 – Home Page Web

SSL 443 – Home Page Web Secured

HTTP2 444 – Second SSL Secured on alternate port for SharePoint

PPTP 1723 – VPN Connections

RDP 3389 – Remote Desktop Protocol (only needed for direct access, if using RWW website, only 4125 is needed)

RWW 4125 – Remote Web Workplace

Optional:

POP3 110 – If using POP3 mail connections

IMAP 143 – Good for iPhones (1st Generation)

IMAP SSL 993 – Even better for iPhones (1st Generation)
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Cisco Router Configuration Cheat Sheet

Networking IEEE Cisco Term Frame Type
TCP/IP 802.3 arpa Ethernet II
Novell
Netware 3.11 or lower (default) 802.3 novell-ether Ethernet 802.3
Netware 3.12 or higher 802.2 sap Ethernet 802.2, Token Ring, FDDI 802.2
AppleTalk on TCP/IP 802.2 snap Ethernet SNAP, Token Ring SNAP, FDDI SNAP
Address Mapping TLA Known Unknown
Address Resolution Protocol ARP IP,  Network, Logical, Layer 3 MAC, Media Access Control, Hardware, Layer 2
Reverse Address Resolution Protocol RARP MAC, Layer 2 IP,  Network, Logical, Layer 3
Routing
Static Routing ip route [dest net] [mask] [next hop address (gateway)] [admin distance] [perm]
ip route [dest net] [mask] [exit interface] [admin distance] [perm]
Distance Vector
Routing Information Protocol RIP
Interior Gateway Routing Protocol IGRP
Link State
Open Shortest Path First OSPF
Hybrid (DV and LS)
Enhanced Interior Gateway Routing Protocol EIGRP
Exterior Gateway Protocols
Border Gateway Protocol BGP
Wildcard Masks
255.255.255.255 any
0.0.0.0 host
Cisco IP Configuration Conventions
Network address of all 0s means “this network or segment”
Network address of all 1s means “all networks”
Node address of all 0s means “this node”
Node address of all 1s means “all nodes”
Entire IP address set to all 0s is the Cisco default route
Entire IP address set to all 1s is the broadcast address for all nodes on the current network

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TCP/IP Networking

IP Subnet Calculator http://www.subnet-calculator.com/
Subnetting guide https://www.comparitech.com/net-admin/subnetting-guide/ 

The IP Subnet Mask Calculator enables Subnet network calculations using network class, IP address, subnet mask, subnet bits, mask bits, maximum required IP subnets and maximum required hosts per subnet.
Basic Subnetting

TCP IP Networking Guidelines
Class Mask Networks Hosts Per Network Range
A B C
Full Class A 255.0.0.0 126 16.77 M 1.X.X.X -126.X.X.X
B 255.255.0.0 16K 65.5 K 128.X.X.X – 191.X.X.X
C 255.255.255.0 2M 254 192.X.X.X – 223.X.X.X
D Multicasting 224.X.X.X-239.X.X.X
E Scientific 240.X.X.X-255.X.X.X
Testing 127.X.X.X
Loopback 127.1.1.1
Non-Routable Private A 255.0.0.0 1 16.77 M 10.0.0.0 – 10.255.255.255
B 255.255.0.0 16 65.5 K 172.16.0.0 -172.31.255.255
APIPA 255.255.0.0 16 65.5K 168.294.0.0 – 168.294.255.255
C 255.255.255.0 255 254 192.168.0.0 – 192.168.255.255
Binary Interval Mask Networks Hosts Per Network
A B C
00000000 254 .0 1 16.77 M 65.5 K 254 + 1 Broadcast (.255)
+ 1 Network Base (.0)
10000000 128 .128 0.5 8 M 32 K 124
11000000 64 .192 2 4.2 M 16,382 62
11100000 32 .224 6 2.1 M 8190 30
11110000 16 .240 14 1.05 M 4094 14
11111000 8 .248 30 524 K 2046 6
11111100 4 .252 62 262 K 1022 2
11111110 2 .254 126 131 K 510 0 Invalid Class C Subnet
(No Hosts)
11111111 1 .255 254 65.5 K 254 1 Class C Host Route
(Dial-Up Networking)

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Classless Inter-Domain Routing (CIDR) And Subnetting

CIDR Suffix # of Class C Networks Interval Mask Total  C Subnets Total  B Subnets Total A Subnets Total  Hosts
/32 1/256 1 255.255.255.255 1 Class C Host Route
(Dial-Up Networking)
/31 1/128 2 255.255.255.254 126 32,766 8,388,606 NA Invalid Subnet
/30 1/64 4 255.255.255.252 62 16,382 4,194,302 2
/29 1/32 8 255.255.255.248 30 8,190 2,097,150 6
/28 1/16 16 255.255.255.240 14 4,094 1,048,574 14
/27 1/8 32 255.255.255.224 6 2,046 524,286 30
/26 1/4 64 255.255.255.192 2 1,022 262,142 62
/25 1/2 128 255.255.255.128 NA 510 131,070 126 Invalid Class C Subnet
/24 1 1 255.255.255.0 1 254 65,534 254 Full Class C
/23 2 2 255.255.254.0 126 32,766 510
/22 4 4 255.255.252.0 62 16,382 1,022
/21 8 8 255.255.248.0 30 8,190 2,046
/20 16 16 255.255.240.0 14 4,094 4,094
/19 32 32 255.255.224.0 6 2,046 8,190
/18 64 64 255.255.192.0 2 1,022 16,382
/17 128 128 255.255.128.0 NA 510 32,766 Invalid Class B Subnet
/16 256 1 255.255.0.0 1 254 65,534 Full Class B
/15 512 2 255.254.0.0 126 131,070
/14 1024 4 255.252.0.0 62 262,142
/13 2048 8 255.248.0.0 30 524,286
/12 4096 16 255.240.0.0 14 1,048,574
/11 8192 32 255.224.0.0 6 2,097,150
/10 16384 64 255.192.0.0 2 4,194,302
/9 32768 128 255.128.0.0 NA 8,388,606 Invalid Class A Subnet
255.0.0.0 1 16,777,214 Full Class A
Subnettting Considerations
Total Sub-Network IDs = 1 per subnet + 1 per WAN Link
Total Host IDs = 1 per host + 1 per router interface
1 Subnet Mask for entire network + 1 unique subnet ID for each physical segment + range of host IDs for each subnet

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Well Known Ports

The port numbers are divided into three ranges: the Well Known Ports, the Registered Ports, and the Dynamic and/or Private Ports.
The Well Known Ports are those from 0 through 1023.
The Registered Ports are those from 1024 through 49151
The Dynamic and/or Private Ports are those from 49152 through 65535
Port Number Type Name Description Security Concerns
1 TCPMUX TCP Port Service Multiplexer
5 RJE Remote Job Entry
7 PING/TRACERT ICMP ECHO – Packet Internet Groper and Trace Route Block from Internet
13 Daytime Network Time Sync with Atomic Clock
18 MSP Message Send Protocol
20 FTP-Data File Transfer Protocol Secure
21 FTP-Control File Transfer Protocol Secure
22 SSH Secure Shell Remote Login Protocol
23 Telnet Telnet Secure
25 SMTP Simple Mail Transfer Protocol Block Relay
29 MSG ICP
37 TIME Time
42 Nameserv Host Name Server
43 Whois WhoIs
49 Login Login Host Protocol
53 DNS Domain Name System Secure
67 BootP-Server Outgoing DHCP Block
68 BootP-Client Incoming DHCP
69 TFTP TFTP – Trivial File Transfer Protocol
70 Gopher Gopher
79 Finger Finger
80 HTTP HTTP
88 Kerberos Secure Encrypted Login
103 X.400 X.400
108 SNA SNA Gateway Access Server
109 POP2 Post Office Protocol
110 POP3 Post Office Protocol
115 SFTP Simple File Transfer Protocol
118 SQL SQL Services
119 NNTP Network News Transfer Protocol
135 Both NetBIOS DCE Endpoint Mapper Block
137 Both NetBIOS NetBIOS Name Service Block
138 Both NetBIOS NetBIOS Datagram Service Block
139 Both NetBIOS NetBIOS Session Service Block
143 IMAP Internet Message Access Protocol
150 NetBIOS NetBIOS Session Service
156 SQL SQL Server
161 SNMP SNMP – Simple Network Management Protocol
179 BGP BGP – Border Gateway Protocol
190 GACP Gateway Access Control Protocol (GACP)
194 IRC IRC – Internet Relay Chat
197 DLS Directory Location Service (DLS)
213 IPX Novell Netware
389 LDAP LDAP – Lightweight Directory Access Protocol
396 Novell Netware over IP
443 HTTPS HTTP over TLS/SSL Enable only if required – otherwise BLOCK
444 SNPP Simple Network Paging Protocol (SNPP)
445 Microsoft-DS Block
458 Apple Quick Time
546 DHCPv6 DHCP version 6 Client
547 DHCPv6 DHCP version 6 Server
563 NTTPS Network News Transfer Protocol over TLS/SSL
569 MSN
636 LDAPS LDAP over TLS/SSL
989 FTPS-DATA FTP Data over TLS/SSL
990 FTPS FTP Control over TLS/SSL
992 TenetS Telnet over TLS/SSL
993 IMAP4S IMAP over SSL
994 IRCS IRC over TLS/SSL
995 POP3S Post Office Protocol 3 over TLS/SSL
Private Ports
1080 Socks
1512 Both WINS Windows Internet Naming Service
INSTANT MESSAGING PORTS
4443 TCP AIM AOL Block or Permit
5190 TCP AIM AOL Block or Permit
3574 TCP ICQ Block or Permit
4000 UDP ICQ Block or Permit
4001 UDP ICQ Block or Permit
5190 TCP ICQ Block or Permit
7320 TCP ICQ Block or Permit
1503 TCP MSN MSN Messenger Block or Permit
1863 TCP MSN MSN Messenger Block or Permit
6891 TCP MSN MSN Messenger Block or Permit
13324 UDP MSN MSN Messenger Block or Permit
13325 UDP MSN MSN Messenger Block or Permit
5010 TCP Yahoo Block or Permit

Click this link for to be directed to a comprehensive port number list on the IANA web site.

Download Common Ports as PDF

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IRQs

IRQ DEVICE PORT
0 Timer
1 Keyboard
2 Video Adapter (maybe be redirected to 9)
3 Serial Port COM2 or COM4 (available) 2F8
4 COM1 or COM3 3F8
5 LPT2 (available) 278
6 Floppy Disk Controller
7 LPT1 (Parallel Port) 378
8 Real-Time Clock
9 Redirected IRQ2 (available)
10 Available
11 Available
12 PS2 Mouse (available)
13 Math Coprocessor
14 Hard Disk Controller
15 Available

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Ethernet Wiring

Pin Straight 568B 568A Cross-Over Phone
1 Orange White Green White Brown Brown White
2 Orange Green Brown White Green White
3 Green White Orange White Green Orange White
4 Blue Blue Blue White Blue
5 Blue White Blue White Blue Blue White
6 Green Orange Green White Orange
7 Brown White Brown White Orange Green
8 Brown Brown Orange White Brown

568A vs. 568B. Which should you use?

There are two accepted standards for 8-wire data network jacks (commonly and incorrectly called “RJ-45.”)

ANSI/TIA/EIA-568-B “Commercial Building Telecommunications Cabling Standard” lists both wiring configurations. T568B is the most prevalent for commercial installations, and was used by AT&T for the original Merlin phone systems. To help you remember, associate “B” with “Bell.”

ANSI/TIA/EIA-570-B “Residential Telecommunications Cabling Standards” recommends T568A

If the installation is residential, choose T568A unless other conditions apply (see below).

  • The two inner pairs of 568A are wired the same as a two-line phone jack.
  • If there is pre-existing voice/data wiring (remodel, moves, adds, changes), duplicate this wiring scheme on any new connection.
  • If project specifications are available, use the specified wiring configuration.
  • If components used within the project are internally wired for either T568A or T568B, use that wiring scheme. Make sure both ends of a cable are wired the same way.

Thanks to phonegeeks.com

25-pair cable color codes for punch-down blocks & connectors

T1/E1 Crossover Cable

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