Computer threat - Network Security

Every TCP package have 'flag bit’ defining content and intention of each package.

Example:

A package with flag bit contain "SYN or SYNCHRONIZE" will undertake to conduct initiation connection from sender to recipient. A package with flag bit contain "ACK" will undertake to inform receiver about sender information.
While a TCP package with beet flag contain "FIN" or "FINISH" undertaking to stop connection from sender to recipient.

To build a TCP connection, need data transfer package between two host, transfer of this data recognized by the name of "TCP Three-Way Handshake" as below picture.

Computer Network Threat

Threat is very harmful to the entire system and also by application at internal and external network.

The threat as follows:

Remote Login - this matter happened when someone capable to connect to a computer and have ability to control to several things related to resource found on the host or computer.

Application Backdoors - some program have special ability to access with long distance (remote access). Some bug program, exactly contain a backdoor or hidden access providing level control the computer and program.

SMTP session hijacking - SMTP is most commonly method used to deliver E-mail. By getting E-mail mailing-list, someone can deliver undesirable E-mail to thousands of or more users. This matter is called unsolicited junk mail or spam.

Spamming conducted with joining SMTP server which not suspect, then deliver thousands of E-mail called redirecting process, so that complicate to detect who is the real sender of the Mail Spam.

Operating system bugs – In application, some operation system have conducive security gap to be exploited illegally.

E-mail bombs - is an Individual attack, someone send hundreds or thousands of E-mail to one address so the victim E-mail cannot accept E-mail anymore.

Macro - To make simple or facilitate procedure an application, many application program permit us to make command which can be run by the program (script). By exploiting ability of script or macro, attacker can cause damage of data at computer.

Virus – Most known to make trouble at computer. The growth of virus from method, way of, making, effectiveness, damage storey, and also speed of spreading is different each other.

Redirect bombs – Hacker or Cracker can use ICMP to change direction of information and attack to other router.

Source routing - At many case, a data package which work through one or some network determined by router pass to route information by the router, but sometime hacker used the package as the real sender.

Another type of computer attack are from (next posted about this) :

Denial of Service (DoS)
Spoofing
Broadcast Amplification
TCP SYN

The method to run the threat above, can be conducted variously including using virus.

Network security - protecting PC

Tapping by hacker is an annoying problem when we are on surfing internet.

We have to learn how to hack but shall be used for protection from attack.

Following is tips and some software assisting to protect PC from online tapping.

Often we forget to protect our PC “attacking” from online tapping when we surf the internet.

Many civil people feel enough in protecting its PC with a program a kind of firewall desktop and anti spy firewall.

In fact, still many gap at firewall which you used, can be exploited by online watcher hacking on your PC

Below is a tips to protect PC from internet tapping in a LAN party, W-LAN or home connection as my experience.

Activated your Firewall:

In course of online tapping or infection, usually the first step do by hacker is collect information and data concerning victim to be tapped. Usually hacker use information compiler tools like “ Nmap” ( http://www.insecure.org/nmap), hereinafter hacker will check open port at victim PC and also TCP/IP package sent from PC into Network. This matter to get specific information is called print finger from victim PC.

The others way, hacker usually try to get deeper information by delivering an E-mail bait to victim (victim will open the e-mail through Microsoft Outlook program which integrated in its Windows). From bait E-mail answered, hence hacker directly can check what kind of E-mail software and server client install in victim PC.

A lot of “software bug” site, discuss about weak of E-mail software and server client according to each version, but I’m not talking about that weak at this post.

So how to avoid that attack ?

The way of which you can use as protection early is firewall desktop. If you do not wish to use special firewall or commercial, hence you enough activate personal firewall that found on Windows XP service pack 2. Comprehend firewall application path and activity which you use in order not to harm you.

Ascertaining your pc clear of Virus and Trojan, before install the firewall.
Configure your firewall with carefully in each application requiring to access online and also access sharing file in existing network.

Encrypt the Important Folder and WebMail connection.

After getting information about victim PC, usually hacker can start tapping, it is of course with two important tools that is " Ethereal" and "ARP-Spoofer". With ARP-Spoofer, hacker can take information which pass by victim PC with Gateway Internet access and that information package can be opened with “Ethereal (http://www.ethereal.com)”.

To overcome matter above, we have to encrypt our Webmail connection through https band. Do not use http band, better avoid to use ftp band and telnet, because can be sabotaged by hacker. You can use SSH connection to replace ftp band or the telnet. The existing constraint is there is very rare web server providing https service and the SSH.

One of the common Mail which use HTTPS is GMail. Whereas for the important and confidential folder in the PC better do Encrypt. Its data content with right click on folder that you want to Encrypt, its way open part: Properties – Advanced – Encrypt content to protect data. But this matter can be done if your XP windows system file is use NTFS type. By use NTFS system file, we also can block out to access rights access certain consumer.

Use Good Firewall.

With DNS spoofing, hacker can do deflection instructing PC victim to spurious website. This deflection is easy to do because DNS protocol is not have any security mechanism. This matter can be prevented by using good firewall application.

At firewall nowadays, usually DNS cache keep with elegantly, so when we ever visit to previous website, hence DNS spoofing we can prevent.

Recognize to access autoexec at registry

If hacker have succeeded tap your pc, usually they always prepare backdoor to facilitate hacking access in other opportunity. One of the effort draw up backdoor is by altering victim pc system file. But this matter can be easy to detect to through antivirus program.

The way of more realistic to all hacker by placing Trojan in our PC, then run through one of the "Autoexec" what running with autoexec in other Windows system. In anticipating this matter, which we do with install additional tools “Autorun” from Sysinternalsi (http://www.systernals.com).

With this tool can display lot of autoexec exist in our system. Autoruns also can show signature from autoexec exist in our pc system. If found autoexec entry which unknown and identify as trigger Trojan, hence Autoruns can turn off it. With this tool, we assisted in eliminating against backdoor which is possible left by hacker in our pc.

Besides trick above, to avoid tapping, suggested do not use User Administrator when surf in internet, then arrange your explorer internet security setting to High Level Security setting.

And don't forget to always Update your Windows, especially when newest update improve many Security system on your PC.

Chipset recognized

The chipset is the heart of the computer and is the hub for all data transfer.
It determines how fast components like the processor, memory, keyboard and various plug-ins can function in relation to each other.

A Chipset is a corps of VLSI chip(Very Large Scale Integration Chips), which vital function execute in a computer system. Each function need one or more chip.

Not all chipsets support all components that you may want with your computer. Before selecting a chipset, decide what features you want with your computer, and then check to see that the chipset supports them.

Below is kind of Chip, replaced by a modern chipset:

1. Memory Controller
   
2. EIDE Controller (Enhanced Integral Drive Electronics) is a new version of IDE and improve maximum of harddisk able to be controlled from 504MB become 8.4GB.
   
3. PCI Bridge (Peripheral Component Interface or Peripheral Component Interconnect) is a local bus standard provide by Intel and working with maximum 33Mhz. The bus wide is 32/64 bit, and transfer speed is 133MB/sec for 32 bit and 266MB/sec for 64bit. PCI dissociating (decouple) processor from bus expansion via bridge.
   
4. RTC (Real-Time-Clock)
   
5. DMA (Direct Memory Access) Controller. DMA is a one of technologies used by some hardware to move data from and to main memory without entangling CPU computer (Processor)
   
6. Keyboard controller
   
7. PS/2 mouse controller
   
8. Secondary cache controller
   
9. Low Power CMOS SRAM control

There is not all Chipset replacing all chip function. Chipset is not upgradeble like CPU, memory or harddisk.

Chipset Premier Manufacturer
The famous Chipset maker company like follows:

1. Intel Corporation:
   
   
   
   • Intel® Q965 Express Chipset
     
   • Intel® 5000P Chipset for Dual-Core Intel® Xeon® Processor 5100 Series and Quad-Core Intel® Xeon® Processor 5300 Series
     
   • Intel® 3100 Chipset for Intel® Core™ Duo processors and Intel® Celeron® M processors on 65nm
     
   • Intel® 3100 Chipset for Dual-Core Intel® Xeon® Processors LV and ULV and Intel® Celeron® Processor 1.66 GHz and 1.83 GHz
     
   • Intel® 3100 Chipset for Intel® Pentium® M and Intel® Celeron® M Processors on 90nm process
     
   • Mobile Intel® 945GME Express Chipset
     
   • Intel® E7520 Chipset for Intel® Core™2 Duo Processors and Intel® Core™ Duo Processors
     
   • Intel® E7520 and Intel® E7320 Chipsets for Intel® Pentium® M and Intel® Celeron® M processors on 90nm process
     
   • Intel® E7520 Chipset for Dual-Core Intel® Xeon® Processors LV and ULV, and Intel® Celeron® Processor 1.66 GHz and 1.83 GHz
     
   • Intel® E7520 Chipset For Intel® Xeon® processors
     
   • Intel® E7501 Chipset
     
   • Intel® E7500 Chipset
     
   • Intel® 945G Express Chipset
     
   • Mobile Intel® 915GME Express Chipset
     
   • Mobile Intel® 910GMLE Express Chipset
     
   • Intel® 915GV Express Chipset
     
   • Intel® 875P Chipset
     
   • Intel® 865G Chipset
     
   • Intel® 855GME GMCH and Intel® 6300ESB ICH
     
   • Intel® 855GME GMCH and Intel® ICH-4
     
   • Intel® 854 Chipset
     
   • Intel® 852GME Chipset
     
   • Intel® 852GM Chipset
     
   • Intel® 845 Chipset
     
   • Intel® 845E Chipset
     
   • Intel® 845GV Chipset
     
   • Intel® 815 and 815E Chipsets
     
   • Intel® 810E2 Chipset
     
   • Intel® 810 Chipset
     
   • Intel® 840 Chipset
     
   • Intel® 440BX AGPset
     
   • Intel® 440GX AGPset
     
   • Intel® 440MX Chipset
     
   • Intel® 430HX PCIset
     
   • Intel® 430TX PCIset
   
   
   
   
2. Silicon Integrated System Corporation (SiS):
   
   
   
   • Intel Core 2 Duo Chipset
     
     
     
     • SiS672FX Fully support DX9, Certified for Windows Vista Premium
       
     • SiS672 Fully support DX9, Certified for Windows Vista Premium
       
     • SiS671FX Fully support DX9, Windows Vista ready
       
     • SiS671 Fully support DX9, Windows Vista ready
       
     • SiS671DX Support FSB 1066MHz and DDR2-667, Windows Vista Ready
       
     • SiS662 PCI Express&DDR2-667 Integrated Chipset For Pentium® D/Pentium®4 Processor
     
     
     
     
   • Intel Pentium 4 Chipset
     
     
     
     • SiS656FX - PCI Express&Dual-Channel DDR2/DDR Chipset For Pentium® D/Pentium® 4 Processor
       
     • SiS649FX - PCI Express&Single-Channel DDR2/DDR Chipset For Pentium® D/Pentium® 4 Processor
       
     • SiS649 - PCI Express&Single-Channel DDR2-533/DDR400 Chipset For Pentium® 4
       
     • SiS656 - PCI Express&Dual-Channel DDR2-667/DDR400 Chipset for Pentium® 4
       
     • SiS655TX - Dual-Channel DDR400 Chipset with HyperStreaming™ Technology for Pentium® 4
       
     • SiS655FX - Dual-Channel DDR400 Chipset for Intel® Pentium® 4 FSB800
       
     • SiS648FX - DDR400 Plus AGP 8X Chipset for Intel® Pentium® 4 HT 800
       
     • SiS661FX - Integrated Mirage™ Graphics Chipset for Pentium® 4
       
     • SiS661GX - Integrated Mirage™ Graphics Chipset for Pentium® 4
       
     • SiS655 - Dual-Channel DDR333 Plus AGP 8X Chipset for Intel® Pentium® 4
       
     • SiS648 - First AGP 8X supporting Chipset with MuTIOL® 1G Technology For Pentium® 4
       
     • SiS651 - The Integrated Graphics Solution for Pentium® 4 with FSB533
       
     • SiS650 - Integrated VGA Solution for Intel® Pentium® 4
     
     
     
     
   • AMD 64 Chipset
     
     
     
     • SiS771 - Integrated Mirage™ 3 Graphics Chipset for AMD Socket AM2 CPUs
       
     • SiS761GX - Integrated Mirage™ 1 Graphics Chipset for AMD Athlon™ 64 FX processors
       
     • SiS756 - First PCI Express Athlon™ 64 FX North Bridge Chipset
       
     • SiS755FX - The First AMD Athlon™ 64 FX North Bridge Chipset
       
     • SiS755 - The First AMD Athlon™ 64 North Bridge Chipset
       
     • SiS760GX - The Integrated Mirage™ 2 Graphics Chipset for AMD Athlon™ 64
       
     • SiS760 - The World First Integrated Chipset for AMD Athlon™ 64
     
     
     
     
   • AMD 64 Chipset
     
     
     
     • SiS771 - Integrated Mirage™ 3 Graphics Chipset for AMD Socket AM2 CPUs
       
     • SiS761GX - Integrated Mirage™ 1 Graphics Chipset for AMD Athlon™ 64 FX processors
       
     • SiS756 - First PCI Express Athlon™ 64 FX North Bridge Chipset
       
     • SiS755FX - The First AMD Athlon™ 64 FX North Bridge Chipset
       
     • SiS755 - The First AMD Athlon™ 64 North Bridge Chipset
       
     • SiS760GX - The Integrated Mirage™ 2 Graphics Chipset for AMD Athlon™ 64
       
     • SiS760 - The World First Integrated Chipset for AMD Athlon™ 64
     
     
     
     
   • AMD athlon XP Chipset
     
     
     
     • SiS748 - SiS AGP 8X and DDR400-supporting Chipset for AMD Athlon™ XP
       
     • SiS741 - The Integrated Mirage™ Graphics Chipset for AMD Athlon™ XP FSB400
       
     • SiS741GX - The Integrated Mirage™ Graphics Chipset for AMD Athlon™ XP FSB333
     
     
     
     
   • South Bridge
     
     
     
     • SiS968 - The Southbridge for Windows Vista Ready
       
     • SiS966 - PCI Express MuTIOL® 1G Media I/O
       
     • SiS966L - PCI Express MuTIOL® 1G Media I/O
       
     • SiS965 - PCI Express MuTIOL® 1G Media I/O
       
     • SiS965L - PCI Express MuTIOL® 1G Media I/O
       
     • SiS964 - MuTIOL® 1G Media I/O
       
     • SiS964L - MuTIOL® 1G Media I/O
       
     • SiS963 - MuTIOL® 1G Media I/O
       
     • SiS963L - MuTIOL® 1G Media I/O
     
     
   
   
3. VIA Technologies
   
   
   
   • K8 Series: AMD Opteron/Athlon 64/Athlon 64 FX
     
     
     
     • VIA K8T900
       
     • VIA K8T890
       
     • VIA K8M890
       
     • VIA K8N890
       
     • VIA K8T800 Pro
       
     • VIA K8N800A (N/IG)
       
     • VIA K8N800 (N/IG)
     
     
     
     
   • P4 Series: Intel® Core™2 Duo, Pentium®, and Celeron®
     
     
     
     • VIA PT890
       
     • VIA PT880 Ultra
       
     • VIA P4M900
       
     • VIA P4M890
       
     • VIA P4M800
       
     • VIA P4M800 Pro
       
     • VIA PN800
     
     
     
     
   • C Series: VIA C7®, C7®-D, C3™-M, VIA C3™ and VIA Eden™, Intel Pentium® and Celeron®
     
     
     
     • VIA CN896
       
     • VIA CN800
       
     • VIA CX700M
       
     • VIA CX700
       
     • VIA CN700
       
     • VIA CN400
       
     • VIA CLE266
     
     
     
     
   • V Series: VIA C7®-M and VIA C7®-M ULV
     
     
     
     • VIA VN896
       
     • VIA VN800
       
     • VIA VX700
     
     
     
     
   • K7 Series: AMD Athlon XP/Duron™
     
     
     
     • VIA KT880
       
     • VIA KT600
       
     
     
   • VIA South Bridge Solutions: VIA Integrated South Bridges
     
     
     
     • VIA VT8251
       
     • VIA VT8237R Plus
       
     • VIA VT8237A
       
     • VIA VT8235
     
     
     
     
   • Embedded & Legacy Chipsets: VIA C3™-M, VIA C3™ and VIA Eden™, Intel Pentium III and Celeron® (Socket 370)
     
     
     
     • VIA PLE133T (I/G)
       
     • VIA PN133 (N/IG
     
     
     
     
   
   
   
   
   
   

Using MDaemon PRO as a MAIL Server

MDaemon is one of the utilized software as server mail besides other mail server software.

Hardware requirement for MDaemeon as a Mail Server is :

For small usage any Pentium Class With RAM 32Mb

For biggest usage min. Pentium III With RAM 128Mb

Operating System: Windows '98, Windows NT, Windows 2000, Windows 2003 (My suggestion is use Windows NT or Windows 2000, Windows 2003 so that security system and the stability can be improved)

Service E-Mail Protocol

There are two protocol which often use in E-mail service as a main protocol:


1. Simple Mail transfer protocol (SMTP)
2. Post Office Protocol Version 3 (POP3

Besides the protocol above, also recognized Internet Mail Access Protocol ( IMAP ) which its function like POP3 with a few excess. Following will be explained function and way of activity for each protocol (See my previous posted about the protocol).

Simple Mail Transfer Protocol (SMTP)
Main function of SMTP is to submit E-Mail from a host to other host in network. This protocol do not have ability to conduct depository and intake of E-Mail from a Mailbox. TCP port protocol for SMTP service is 25, representing service standard port SMTP. Because SMTP do not have depository ability in mailbox E-mail, hence needed other protocol to run the function that is POP3 and IMAP.

From E-Mail client side, SMTP server represent medium to conduct connection outgoing or delivering message. While for the incoming of connection used by POP3 protocol.

Post Office Protocol version 3 (POP3)
Version 3 is a POP Protocol, more popular as a POP3 in this time. This protocol function is to get E-Mail in mailbox for every user in server mail, what usually also function at the same time as a SMTP server. As have been explained previously that SMTP do not have depository mechanism of E-Mail to mailbox and distributing it every user, so that POP3 protocol to take the function. POP3 server keep the E-Mail of every user for temporary before finally download by user use E-Mail client like Outlook and also Eudora. In course of the intake of E-Mail Client Connected to the Mail server use POP3 protocol at TCP port 110.

Function of DNS server in Email service
In E-Mail DNS server service personate indicator to the route an E-Mail. If there are an E-Mail, DNS server will check the name of domain that found on address of target.

E-Mail Services in LAN
E-Mail service in LAN environment generally aim to facilitate coordination between internal of an organization. The Scope of LAN in fact can be extended in WAN scale. This mode is not used public network or Internet.



Email service in WAN

Forwarding of E-Mail in public network using internet or WAN, an E-Mail will passed through some server, before is finally accepted by address of target. As have been explained at previous, DNS server function is vital as indicator to route passed by the email.

sending email through internet can be use by: Relay SMTP Server and MX Record at DNS Server. To get an email can be choose with ETRN, Domain POP, Multi POP, SMTP.

Setting MDaemon at LAN

MDaemon can be used at LAN to send and received an E-mail like Email via WAN.
There are three step to configure MDaemon at LAN:



1. Make Domain at Local Network
2. Make Account and Mailbox each user
3. Configure E-Mail client each user

Setting Primary Domain
First step of server mail configuration is to make domain for the account of E-Mail in network. Because you will only using it in local network which not connected to the internet, hence you can make to the name of domain freely without needing registration to Internic and also other registration.

Open the Main Window of MDaemon, then Setup -> Primary Domain.


Domain/ISP is a main tab of Primary Domain Configuration that contain of Primary Domain Server mail. Fill the form as below:



1. Domain Name: (fill with organization domain)
2. HELLO Domain: (name of domain which [is] used in SMTP instruction HELLO/ehlo in process delivery of E-Mail.)
3. Machine Name: (Domain Name)
4. Domain IP: (Computer IP at Local Network)
5. Bind listening sockets to this IP only: (Leave it blank for single Domain, usually this fill use for multiple domain)
6. ISP or Smart host’s IP or domain name: (Leave it blank for E-mail at LAN)

Other fill using for WAN email account purposed.

Create Account Mail
Create Account to be used in LAN environment and internet use menu and way of which is same. An account can relate to internet hence must be done some configuration according to delivery method and selected acceptance.
For LAN purposed, create the account and password determine to the domain only.
To create the account choose Account -> New Account.



Stuffing configuration for the tab of Account shall be as follows:



1. Full Name: filled with complete name of user
2. Mailbox Account: Filled with name to be used as E-Mail address
3. Allow this account to be accessed with POP/IMAP mail clients: is used to give rights so that the account can be accessed from POP client /IMAP like Outlook and Eudora.
4. Account password: Password for the account.
5. Comments on this Account: Column to fill in various note lionized for the account.

To see mailbox tab content click Mailbox at Account Editor menu.
Mailbox configuration conducted to every account. This shares function to determine depository location of E-Mail every user in server MDAEMON before downloaded by pertinent user.


The Menu Mailbox content shall be as follows.



1. Message directory: location of directory path where E-Mail keep
2. Storage Format: representing depository format of file in folder for every user.
3. Enable automatic extraction of MIME encoded attachments: if this choice is activated, MDAEMON will extract E-Mail attachment which have found by MIME format to every E-Mail which enter. This facility is used especially for the client of E-Mail which do not have ability of MIME file extract.

Setting MDaemon at WAN
Steps to conduct MDAEMON configuration for internet connection shall be as follows:

1. Modem Configuration, DialUp Networking to ISP, RAS DialUp/DialDown in MDaemon.
2. DNS Configuration.
3. Sending Email Configuration.
4. Receipt Email Configuration.

RAS DialUp/DialDown
Before doing configuration at this session, we have to check: Modem already installed and DialUp connection to the ISP via Internet has been installed and running well.

For Setting RAS DialUp at MDaemon with press F7 or Setup -> RAS Dialup/dialdown.



Dialup Setting Tab and ISP Logon Setting is a main menu must enter for MDaemon connected to the Internet. At Dialup tab setting there are some configuration type as follows:

1. Enable RAS dialup/dialdown engine: To activation Dialup function.
2. Make this many attemps to establish a session: Is used to determine how many times MDAEMON repeat dial to ISP.
3. After dialing, wait this many seconds for a valid connection: This shares determine how long MDAEMON await to get link to ISP
4. Connection persistence: you can decide MDAEMON will continuously
   connect, or determined by] certain time interval (in minute) before finally MDAEMON disconnect with ISP, if there is no activity.

The other Important things for RAS Dialup Settings menu is containing ISP Logon Settings tab of information concerning ISP account.


Configuration type in this shares shall be as follows:



1. Use any currently active dialup session: To determine what is MDAEMON will use conection which is active to deliver of and acceptance of E-Mail,
   so that no need to dial.
2. Logon name: Filled with got account from your ISP.
3. Logon password: Password for the logon to ISP.
4. Use this RAS dialup profile: Is available internet connection type choice combo box. This box present networking dialup choice as according to internet connection which have installed in Windows.

DNS Configuration
Besides usage of Primary Domain which enlist, also need DNS configuration, MDAEMON use for look domain address in internet.

Configuration of DNS conducted from DNS tab at Primary Domain configuration menu.


DNS number got from your ISP.

Sending E-mail using SMTP Relay

This method using your ISP SMTP server or hosting Mail as a relay machine to the Internet. (same parameter with MDaemon on LAN, except: the ISP smart host 's IP or domain name with your SMTP ISP Server, then choose Send every outbound email message to this host).


Receive E-mail using MultiPOP
E-Mail address is usually equiped by POP3 facility for download of E-Mail from server to client like Outlook and Eudora. In MultiPOP Outlook role method as E-mail client replaced by MDAEMON later on distribute the E-Mail to every user.

MultiPOP can use as following:
1. If ISP or hosting web do not provide DomainpPOP facility and also ETRN.
2. MultiPOP using as ETRN and DomainPOP
3. You wish free E-Mail service host in MDAEMON, so that user in network do not
   need connection to internet to get the E-Mail.
   
   
   The configuration as follows:
   
   
   
   1. Enable MultiPOP mail collection for this account: to activate MultiPOP function
   2. Server: POP3 server name - got from ISP
   3. Logon: User account in POP3 server
   4. Password: Password in POP3 server or APOP shared secret
   5. Use APOP (password field contains shared secret: Make this active if authentication password is APOP
   6. a copy of message on POP server: Keep the E-mail in POP3 server even MDaemon already downloaded, later you can read your mail from other location.
   7. messages once [xx] or more have accumulated (0 = never): Maximum Email keeping in POP3 server
   8. download messages larger than [xx] kb (0 = no limit: The limit of E-Mail size download.

>>>>  I will continue this Mail server setting compare with others apps.

Internet Protocol keyword

Most Windows have the ability to define Internet Protocol (IP) packet filters for protocol numbers. IP packet filters are commonly used to restrict traffic in and out of each interface.

We used this Protocol number to configure firewalls, routers and proxy. Next session i want to write about network firewall. This is as reference only, so if you want to know more about this visit the associated, like Microsoft, cisco, etc..etc

Internet Protocol Number:

Decimal	Keyword	Protocol
0		Reserved
1	ICMP	Internet Control Message
2	IGMP	Internet Group Management
3	GGP	Gateway-To-Gateway
4	IP	IP in IP (Encapsulation)
5	ST	Stream
6	TCP	Transmission Control
7	UCL	UCL
8	EGP	Exterior Gateway Protocol
9	IGP	Any Private Interior Gateway
10	BBN-RCC-MON	BBN RCC Monitoring
11	NVP-II	Network Voice Protocol
12	PUP	PUP
13	ARGUS	ARGUS
14	EMCON	EMCON
15	XNET	Cross Net Debugger
16	CHAOS	Chaos
17	UDP	User Datagram
18	MUX	Multiplexing
19	DCN-MEAS	DCN Measurement Subsystems
20	HMP	Host Monitoring
21	PRM	Packet Radio Measurement
2	XNS-IDP	Xerox NS IDP
23	TRUNK-1	Trunk-1
24	TRUNK-2	Trunk-2
25	LEAF-1	LEAF-1
26	LEAF-2	LEAF2
27	RDP	Reliable Data Protocol
28	IRTP	Internet Reliable Transaction
29	ISO-TP4	ISO Transport Protocol Class 4
30	NETBLT	Bulk Data Transfer Protocol
31	MFE-NSP	MFE Network Services Protocol
32	MERIT-INP	MERIT Internodal Protocol
33	SEP	Sequential Exchange Protocol
34	3PC	Third Party Connect Protocol
35	IDPR	Inter-Domain Policy Routing Protocol
36	XTP	XTP
37	DDP	Datagram Delivery Protocol
38	IDPR-CMTP	IDPR Control Message Transport Protocol
39	TP++	TP++ Transport Protocol
40	IL	IL Transport Protocol
41	SIP	Simple Internet Protocol
42	SDRP	Source Demand Routing Protocol
43	SIP-SR	SIP Source Route
44	SIP-FRAG	SIP Fragment
45	IDRP	Inter Domain Routing Protocol
46	RSVP	Reservation Protocol
47	GRE	General Routing Encapsulation
48	MHRP	Mobile Host Routing Protocol
49	BNA	BNA
50	SIPP-ESP	SIPP Encap Security Payload
51	SIPP-AH	SIPP Authentication Header
52	I-NLSP	Integrated Net Layer Security TUBA
53	SWIPE	IP With Encryption
54	NHRP	NBMA Next Hoop Resolution Protocol
55 - 60		Unassigned
61		Any Host Internal Protocol
62	CFTP	CFTP
63		Any Local Network
64	SAT-EXPAK	SATNET and Backroom EXPAK
65	KRYPTOLAN	Kryptolan
66	RVD	MIT Remote Virtual Disk Protocol
67	IPPC	Internet Pluribus Packet Core
68		Any distributed File System
69	SAT-MON	SATNET Monitoring
70	VISA	VISA Protocol
71	IPCV	Internet Packet Core Utility
72	CPNX	Computer Protocol Network Executive
73	CPHB	Computer Protocol Heart Beat
74	WSN	Wang Span Network
75	PVP	Packet Video Protocol
76	BR-SAT-MON	Backroom SATNET Monitoring
77	SUN-ND	SUN ND PROTOCOL-Temporary
78	WB-MON	WIDEBAND Monitoring
79	WB-EXPAK	WIDEBAND Expak
80	ISO-IP	ISO Internet Protocol
81	VMTP	VMTP
82	SECURE-VMTP	Secure - VMTP
83	VINES	VINES
84	TTP	TTP
85	NSFNET-IGP	NSFNET-IGP
86	DGP	Dissimilar Gateway Protocol
87	TCF	TCF
88	IGRP	IGRP
89	OSPFIGP	OSPFIGP
90	SPRITE-RPC	Sprite RPC Protocol
91	LARP	Locus Address Resolution Protocol
92	MTP	Multicast Transport Protocol
93	AX.25	AX.25 Frames
94	IPIP	IP-within-IP Encapsulation Protocol
95	MICP	Mobile Internetworking Control Pro
96	SCC-SP	Semaphore Communication Sec. Pro
97	ETHERIP	Ethernet-within-IP Encapsulation
98	ENCAP	Encapsulation Header
99		Any Private Encryption Scheme
100	GMTP	GMTP
101-254		Unassigned
255		Reserved