This document discusses the history and types of firewalls. It describes early circuit-level firewalls developed at AT&T and DEC in the 1980s. Packet filtering firewalls screening network traffic based on IP and TCP/UDP headers were introduced by Cisco in the early 1990s. Application layer firewalls called proxy firewalls were developed in the late 1990s, screening traffic based on application protocols like HTTP, FTP, and SMTP. The document also discusses stateful packet inspection, demilitarized zones (DMZs), and common firewall threats.

1. o
o
o
o
o
o
Nosstateful

2. Stateful
DMZ
Proxy

3. download
1
Firewall

4. 5
DEC
8
AT&T Bell Laboratories
.
. SEAL
"SEAL"
Cisco
2
Packet Filtering Firewalls
Cisco
4
Jeff Mogul
5
Digital Equipment Corporation
6
Dave Presetto
7
Howard Trickey
3
8
9
circuit level firewalls
Bill Cheswick
11
Marcus Ranum
12
Gene Spafford
13
Application Layer Firewalls
14
Proxy-Based Firewalls
15
Bob Braden
16
Annette DeSchlon
17
Visas
18
Visual Integration
19
Check Point Software
20
Scott Wiegel
21
Global Internet Software Group
22
Kernel Proxy architecture
10
DEC

5. "
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.
.
23
fireWall

6. URL

7. -
DsL
patch

8. 24
Packet Filtering

9. mini Computer
DVD
CD

10. E-mail
Trojan
E-mail Worms
Worm
25
E-mail Worms
Simple Mail Transfer Protocol
26
26
SMTP

11. Dial up
upgrade
upgrade
un-install
memory CPU

12. dialup
TCP
TCP
TCP
27
No Interface
Circuit-LeveL
28

13. Nosstateful packet
IP

14. Stateful Packet
UDP TCP
TCP
FTP
Stateful
TCP
TCP
HTTP
PC

15. DMZ
DMZ

16. :
IP
IP
IP
IP
: , ,,.
64 16
236 52
IP
IP
.
IP
IP
69,254,15,25
www
. .
goole
com
.
browser
http
:
29
domain names
30
client
31
server

17. 32
IP
TCP
.
34
HTTP
UDP
FTP
ICMP
.
SMTP
SNMP
FTP
.
"
x-rated
"
"
x-rated " rated
" x
"
32
Internet Protocol
Transmission Control Protocol
34
Hyper Text Transfer Protocol
35
User Datagram Protocol
36
File Transfer Protocol
37
Internet Control Message Protocol
38
Simple mail transport protocol
39
Simple Network Management protocol
33
( )
FTP
(
HTTP
)

18. LAN
resource
.
.
IP TCP
:
40
40
Accept Mode
Blocking Mode
41

19. 42
.
.
TCP/IP
header
:
FTP Telnet
Telnet
header
header
IP
:
IP
.
IP
IP
.
42
Response Mode
Identifier & Fragment Offset
43

20. .
.
44
IP
.
IP
.
:
header
:
ftp
TCP
ftp
Telnet
.
.
:
46
:
TCP
44
Pocket Filtering Router
Acknowledgment
46
TCP code Bits
45
SYN=1

21. TCP
"
"
TCP
.
.
:
.
.
header
TCP

22. :
.
(backdoor)
.
e-mail
e-mail
SMTP
e-mail
e-mail
.
backdoor
.
.
.
.
e - mail
.
47
e -mail
e-mail
Remote Login
Application Backdoor
49
SMTP session hijacking
50
spam
51
Operating system bugs
52
Denial of service
48
e-mail
E- mail

23. .
.
.
.
backdoor
cookie
ICMP
.
e-mail
.
.
53
Macros
Spam
55
Redirect bombs
56
Source routing
54
e-mail
e-mail

24. .
.
DMZ Proxy
proxy
.
.
:
online
FTP
-
57
DMZ
DMZ
.
DMZ
DMZ
DMZ
57
Demilitarized Zone
gateway

25. NAT

26. ZonAlram pro
2008
ZoneAlarm
Shield Pro FireWall
2008
repair
Hauri
inbox
Prisma FireWall
TCP
Panda
.
. .

27. URL
.
proxy
proxy
http
.
free proxy

28. :
www.homenethelp.com/web/ howto/free-firewall.asp
http://www.all-internet-security.com/top_10_firewall_software.html
http://networking.anandsoft.com/ad vantages-of-hardware-firewalls.html
http://www.faqs.org/qa/qa-4838.html
http://www.smallbusinesscomputing.c om/webmaster/article.php/3103431
http://personal-firewall-software-review.t optenreviews.com/hardware-firewalls-vssoftware-firewalls.html
http://www.webopedia.com/didyouknow/hardwaresoftware/2004/firewall_types.asp
http://www.evaluateit.co.uk/small_business/firewalls.html
http://cms-london.com/ articletext.php?id=105
http://www.srco.ir/Articles/TipsView.asp?ID=254
http://www.alliancedatacom.com/firewall-tutorial.htm
http://www.npc-rt.ir/newsdetail-fa-20.html
http://fa.wikipedia.org/wiki
http://atalebi.com/articles/show.asp?ID=427
http://www.iran20.ir/view.asp?id=50005879719100001
http://forum.sohail2d.com/viewtopic.php?t=9183
http://www.iritn.com/?action=show&type=news&id=7216
http://www.microrayaneh.com/Articles/Internet/Firewall2.htm
http://www.indstate.edu/ect/ECT680/fall03_papers/Pramod.pdf