?????????????: ????? ???????????????
???????
????????????????????????????????????????????????????????????? Port ??????????????????? ???????????????????????????????????? Internet ??????????????????????????????? security ???????????????? Port ????????????????????????????????????????? Port ?????????????????????????????????????????? Compromise ??????????????????????????????????????????????????????????????????????????????????? Port ?????????????????????????????? Port ?????????
?????????????????????? Port
????????? Application ?????? layer ??? ? ?????? TCP (Transmission Control Protocol) ???? UDP (User Datagram Protocol) ??????????? Port ?????????? Port ????????? 16 bit ???????????? 0 ??? 65535 ??????? Port ?????????????????? service ???????????????????? ?????????? ??????? Port ?????????????????????????? service ??? ??????????? OS (operating system) ?????? ?????????????????????? ?????????????????????????????????????????????????????????????????????????????????? ??? Internet Assigned Numbers Authority (IANA) ?????????????????????????????????????? Port ??? Port ??????????????????????? Service ?? ????????????? Request For Comments (RFC') 1700 ???????????? ???????? TCP Port ??????? 23 ??? Service Telnet ??????????? UDP Port ??????? 69 ?????? Service Trivial File transfer Protocol (TFTP) ?????????????????????????????? File/etc/services ?????????????? ??????? Port ??????????????????????????? Transport Protocol ???????????? Protocol ??????????????? UPP ???? TCP ???????? ??????? Port ????????????? ????????????? Protocol ??????????
?????????????? Port ?????????????? 2 ?????? ???????????????? RFC' 1700 (?????????? Download ?????????????? ftp://ftp.isi.edn/in-notes/rfc'1700.txt) ??? well known Ports ??? Registered Ports
- Well Known Ports ????????? Port ????????????????????????????? Privileged User (?????????????????????) ??? port ?????????????????????????????????????????????????????????????? ???????????????????? service ????????? (???????????????????????) ???????? ?????????????????? Port ???????????? Service ???? ?
- Registered Ports ?????? Port ??????? 1024 ?????? ???? IANA ??????????????
?????????????? Port
????? Transport layer segment ?????????????????????????????????? Port ????????????????? ???????????????????? (Destination host) ????? Port ?????????????????????????? Application ?????????? ?????????????????????????? Segment ?????????????????? Application ??????????? "Demultiplexing" ????????????????????????? (Source host) ????????????????????????????? Application ???????? header ?????????? segment ???????? "Multiplexing" ????????????????????????????? ? ?? ??? ????????????????? 1 ??????????????????????????????????? ?????????? Demultiplexing ?? ? ??????????????????????????????????????????????????????? ? ?????? ??????????????? ?????????? Multiplexing ?? ? ??????????????????????????????????????????????????????? Demultiplexing ????????? 1
?????? 1
??????? Port ???????? 32 bit ?????? TCP ??? UDP header ?????? 16 bit ?????????????? Port ???????????????? ?????? 16 bit ???????????????? Port ????????????????? ??????????????? 2
?????? 2
TCP ???? UDP ???????????????????? Port ?? header ??????????????? Application ?????????????????????? ? ??????? Port ?????????????????????????????????????????????????????????????????????????? process ??????? 1 process ??????????????
??????????????????????? "Well know Ports" ???? Port ?????????????????? ??????????????????????????? (Remote Computer) ????????????????????????????? Port ????????????????? Service ????????? ? ????????????????? Port ???????????????????? Dynamically Allocated Port ???? Port ?????????????????? assign ?????????? ???????? assign ??????????? Port ????????????????????????????????????????????????????????????? ? ??????? ? ??? ??????????????????????????????? assign ??????? Port ??????
?????????? ?????????????????????????? Service Telnet ??????????????????????? assign ?????????? Dynamic Port (???? 3044) ????????????? Port ?????????? 23 ????????? assign ??????? Port ??????????? 23 ???????????? Well Known Port ?????? Service Telnet ???????????????????????????????????????????? Port ??????? 23 ????????????????? ?????????? Port 3044 ??????????????????
??????????????? Port ?????????? IP ??????????? Socket ??????????????????????????????????????? Network process ????????????????????????????? Internet ?????? Socket ????????????? Socket ???????????????????? ???????????????????????????????????????????????????? Connection oriented protocols
?????????????? ?????????????? 2 ?????????? Service Telnet ???????????????????????????????? ??????????????????????? assign ??????? Port ???????????????????????? ???????????? Port ??????????????????????????????????????? 3 ??????????????????????????????? Port ?????????? IP ???????????????????????????????????????????????? Internet connection ????????????????????????????????????????
?????? 3
Active ??? Passive Ports
????????????????????????????????????? Port ????? ?????????????????? Active ??? Passive Port
????????????????????? TCP ?????????????? 2 ??????? Passive ??? Active Connection Passive connection ??? ???????????? Application process ??????? TCP ????????? Port ??????????????????????????? Source Host ????? TCP ??????????????????????????????????????? Port ??? ????????????? Active TCP ??????? Application process ???????????????????? Port ??????
References
An Explanation of Ports. http://www.sans.org/infosecFAQ/securitybasics/ports.htm
Enders, Matthias and Hayes, Steve. "2.10 Ports and Sockets." "TCP/IP Tutorial and Technical Overview." 5th Edition. June 1995.
http://www4.ulpgc.es/tutoriales/tcpip/pru/3376c210.htm#sokapi. 29 January 2001.
Hunt, Craig. "2.7 Protocols, Ports, and Sockets." "TCP/IP Network Administration." 2nd Edition. December 1997.
http://www.dimas.burnet.ru/oreilly/cdrom/tcpip/ch02_07.htm. 29 January 2001.
Kurose, James F. and Ross, Keith W. " 3.2 Multiplexing and Demultiplexing Applications." "Computer Networking: A Top-Down Approach Featuring the Internet."
http://www-net.cs.umass.edu/kurose/transport/fund.html, 1 February 2001.
Pavincich, Marco. "TCP/IP In More Detail." 04 July 1997.
http://home.mira.net/~marcop/tcpip_detail.htm, 1 February 2001.
Postel, J. and Reynolds, J. "RFC1700 Assigned numbers." October 1994.
ftp://ftp.isi.edu/in-notes/rfc1700.txt. 25 January 2001.
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