r4.dvi

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1 :???? ( : ) ( 1)? 1:? Google Web ping % /sbin/ping PING museuhistoriconacional.com.br ( ): 56 data bytes 64 bytes from : icmp_seq=0 ttl=228 time= ms 1

2 64 bytes from : icmp_seq=1 ttl=228 time= ms 64 bytes from : icmp_seq=2 ttl=228 time= ms 64 bytes from : icmp_seq=3 ttl=228 time= ms ^ trl- % 320msec 160msec 160msec 1.2? ( ) : a. PU b. 1 1 c. 1 d. 1 e. (LAN Local Area Network ) (WAN Wide Area Network ) 1.3 option ( ) (2 ) 2

3 ( m m) LAN 2: ( ) ( 2) ( ) ( ) ( ) 1 LAN 1 LAN WAN ( ) WAN WAN 1-1 (NSPIXP Network Service Provider Internet exchange Point) ( 3) 1.4 3

4 LAN WAN WAN WAN NSPIXP WAN 3: ( ) ( ) ( ) A B D E F AtoF BtoE AtoF AtoF BtoE BtoE 4: 4 A F D F D F D D D F 4

5 B E D B E A F 1 1 (IPv4) (IP ) 4 (32 ) IP (16 ) 0a a google.co.jp? IP IP 16 1 OS 1.5 /* recv.c -- packet receiving example. */ #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> main(int argc, char *argv[]) { int fd, len, fromlen; char buf[100]; static struct sockaddr_in adr; adr.sin_family = AF_INET; A F E 5

6 } adr.sin_addr.s_addr = INADDR_ANY; adr.sin_port = htons(atoi(argv[1])); if((fd = socket(pf_inet, SOK_DGRAM, IPPROTO_UDP)) < 0 bind(fd, (struct sockaddr*)&adr, sizeof(adr)) < 0) { perror("socket: "); exit(1); } while(1) { len = recvfrom(fd, buf, 100, 0, 0, &fromlen); if(len < 0) { perror("recvfrom: "); exit(1); } write(1, buf, len); } #include... main fd ( ) len fromlen buf adr fd bind ( ) OS ( ) recvfrom OS recvfrom buf recvfrom write IP ifconfig( /sbin/ifconfig ) ifconfig ( ) % /sbin/ifconfig em0: flags=8843<up,broadast,running,simplex,multiast> mtu 1500 options=3<rxsum,txsum> inet netmask 0xff broadcast ether 00:0f:ea:10:4c:71 media: Ethernet autoselect (1000baseTX <full-duplex>) status: active plip0: flags=8810<pointopoint,simplex,multiast> mtu 1500 lo0: flags=8049<up,loopbak,running,multiast> mtu inet netmask 0xff % inet(ip ) IP IP % gcc -o recv recv.c % recv ( ) ( ) 6

7 /* send.c -- packet sending example. */ #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> main(int argc, char *argv[]) { int fd; char buf[20]; int len; struct sockaddr_in adr; adr.sin_family = AF_INET; adr.sin_addr.s_addr = INADDR_ANY; if((fd = socket(pf_inet, SOK_DGRAM, IPPROTO_UDP)) < 0 bind(fd, (struct sockaddr*)&adr, sizeof(adr)) < 0) { perror("socket: "); exit(1); } adr.sin_port = htons(atoi(argv[1])); adr.sin_addr.s_addr = inet_addr(argv[2]); while((len = read(0, buf, 20)) > 0) { if(sendto(fd, buf, len, 0, (struct sockaddr*)&adr, sizeof(adr)) < 0) { perror("sendto: "); exit(1); } } } sendto IP % gcc -o send send.c recv % send IP hello. this is a pen.... recv ( trl- ) send % less t aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb ccccccccccccccccccccccccccccccccccccccccccccccccccccccccc ddddddddddddddddddddddddddddddddddddddddddddddddddddddddd aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb... % cat t t t t send recv ( ) aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb ccccccccccccccccccccccccccccccccccccccccccccccccccccccccc 7

8 ddddddddddddddddddddddddddddddddddddddddddddddddddddddddd... aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb bbbbbbbbbbbbbbbbbbb?...??? ( 4096 ) (layered architecuture) FAX ( 5) 5: ( )? ( 6) 8

9 OK 2 OK 4 OK : ( ) ( ) 2.2?? ( ) a. a. ( ) a. b. c. d. e. 9

10 ( ) ( ) ( ) ( ) 2.3 OSI ISO( ) (OSI Open System Interconnect) 7 OSI 7 7 Application Application a) Presentation Presentation Session Session b) Transport Transport c) Network Network Network Network d) Data Link Data Link Data Link Data Link e) Physical X Physical Physical Y Physical 7: OSI 7 1. ( e) 2. ( d) 3. ( c) 4. ( b) a OSI 5. / / ( ) 10

11 ( ) ( TP/IP ) 2.4 TP/IP TP/IP TP/IP IPv4 IPv6 IPv4 TP/IP 8 rwho tftp wall telnet ftp smtp nntp rlogin rcp rexec nis NFS Application Presentation Session UDP TP Transport Internet Protocol (IP) Network loopback Ethernet Driver PPP Data Link Ethernet Serial/ADSL Physical 8: TP/IP IP(Internet Protocol) ( ) IP P LAN? IP UDP(User Datagram Protocol) TP(Transmission ontrol Protocol) UDP TP TP/IP 11

12 3 3.1 LAN LAN (Ethernet) LAN 1970 Xerox IEEE ( 2 ) ( 9) Hub Switch 9: Ethernet 1 48 MA MA 1 ( ) ( ) SMA/D(arrier Sense Multiple Access/ollision Detection) SMA/D ( ) Mac ( ) 10Mbps 1Gbps 100m / IP ( 3 ) LAN WPA(Wi-Fi Protected Access) WPA2(Wi-Fi Protected Access 2) WPS(Wi-Fi Protected Setup) ( LAN ) Mbit/ 3 4Mbit/ 3 LAN WEP(Wireless Encription Privacy) 2 12

13 3.2 option LAN 2 ( ) 2 / PPP (Point-to-Point Protocol) PPP ADSL 8 ( )? A B 2 B A B A A A ( )? 2 (VPN) 3.3 Unix ifconfig ( ) ifconfig netstat -I netstat -I netstat -I 2 ( ) % netstat -I fxp0 1 input (fxp0) output packets errs bytes packets errs bytes colls 13

14 ^ ontrol- % IP IP TP/IP IP 32 IP IP ( ifconfig IP ) 1 IP IP ( ) 1 IP IP ( IP ) ( ) IP 1 ( ) IANN(Internet orporation for Assigned Names and Numbers) JPNI ( A B ) /24 / 1 32 ( ) netmask 0xffffff00 14

15 ( ) IP IP 32 IP IP(IPv6) IP 128 IPv4 IP ( ) ( ) NAT(Network Address Translation) NAT IP IPv6 ( ) IP ping ping ping IP IP / 4.2 IP ( ) 3?

16 IP 32 ( ) ( 10 ) 1 ( A B ) (default) A B 10: 1 (aggregate) / / /16 1 ( 11) 6 ( ) traceroute

17 ( /16) / / /24 11: ( ) % /usr/sbin/traceroute traceroute to museuhistoriconacional.com.br ( ), 64 hops max, 40 byte packets 1 plalagw ( ) ms ms ms ( ) ms ms ms ( ) ms ms ms ( ) ms ms ms ( ) ms ms ms ( ) ms ms ms ( ) ms ms ms ( ) ms ms ms 9 xe a21.tokyjp01.jp.ra.verio.net ( ) ms ms ms 10 xe r20.tokyjp01.jp.bb.verio.net ( ) ms ms ms ( ) ms ms ms 12 p r21.snjsca04.us.bb.verio.net ( ) ms ms ms 13 xe r20.snjsca04.us.bb.verio.net ( ) ms ms ms 14 interconnect-eng.sanjose1.level3.net ( ) ms ms ms 15 so bbr2.sanjose1.level3.net ( ) ms ms ms 16 as-1-0.mp1.miami1.level3.net ( ) ms as-0-0.mp2.miami1.level3.net ( ) ms as-1-0.mp1.miami1.level3.net ( ) ms 17 ge-9-1.hsa2.miami1.level3.net ( ) ms unknown.level3.net ( ) ms ge-9-0.hsa2.miami1.level3.net ( ) ms 18 unknown.level3.net ( ) ms ms ms 19 diveo-tb-mia-stm1.ipb.diveo.net.br ( ) ms ms ms 20 h ipb.diveo.net.br ( ) ms ms ms ( ) ms ms ms 22 cl-s cpe.rt.rjo.ipaccess.diveo.net.br ( ) ms ms ms 23 anita.visualnet.com.br ( ) ms ms ms 17

18 4.3 DNS IP IP ( ) Unix /etc/hosts IP ( OS ) localhost piyo01... IP IP LAN IP? IP DNS(Domain Name System) (DNS UDP IP ). ( ) DNS DNS (TLD Top-Level Domain) TLD.jp.ac.jp.co.jp.ac.jp.tsukuba.ac.jp DNS.otsuka.tsukuba.ac.jp DNS IP ( ) 18

19 TLD.jp( ).uk( ) TLD.com( ).edu( ) gtld(generic TLD TLD) IP IANA gtld IANA (.com VeriSign ) TLD ( JPRS) gtld DNS ( IP ) nslookup DNS nslookup IP % /usr/sbin/nslookup Server: utogw.gssm.otsuka.tsukuba.ac.jp Address: Non-authoritative answer: Name: Addresses: , , % IP 3 WWW IP DNS? DNS DNS DNS? DNS DNS UDP TP TP UDP 2 UDP IP UDP UDP ( IP ) ( ) (best effort) UDP UDP ( ) 19

20 TP (reliable) TP / ( ) TP W TP checksum=10010 sender ok 2ok 3ok receiver 12: TP 5.2 IP ( ) ( ) 20

21 TP UDP (well-konwn ports) TP UDP ( IANA ) Unix /etc/services TP UDP netstat -f inet netstat -f inet TP UDP % netstat -f inet less Active Internet connections Proto Recv-Q Send-Q Local Address Foreign Address (state) tcp4 0 0 sma.nfsd smp.798 ESTABLISHED tcp4 0 0 sma.nfsd smri ESTABLISHED tcp4 0 0 sma smr04.x11 ESTABLISHED tcp4 0 0 sma.canna smm ESTABLISHED tcp4 0 0 sma.nfsd smr ESTABLISHED tcp4 0 0 sma.canna smri ESTABLISHED tcp4 0 0 sma.nfsd smri ESTABLISHED tcp4 0 0 sma.nfsd smri ESTABLISHED tcp4 0 0 sma.nfsd smr ESTABLISHED tcp4 0 0 sma.nfsd utogw.788 ESTABLISHED tcp4 0 0 localhost.smtp *.* LISTEN udp4 0 0 localhost.ntp *.* udp4 0 0 sma.ntp *.* udp4 0 0 localhost.1019 localhost.1022 % tcp4 udp4 IPv4 TP UDP. /etc/services TP ( ) 6 OSI 7 3 TP/IP ( ) TP/IP ( ) 21

22 TP/IP WWW /sbin/ping (ping ) Windows 4-2. /usr/sbin/traceroute Windows tracert 4-3. nslookup IP WWW 4-4. send.c/recv.c ifconfig -a IP 2 netstat -f inet netstat send.c/recv.c netstat -f inet TP/IP netstat Windows netstat -a 4-7. netstat 1 1 Windows netstat -e 1 : ( ) rlogin utogw utogw Windows ( ) 7 7 : recv.c send.c

r4.dvi

r4.dvi 16 4 2016.5.11 1 1.1 :? PC LAN Web?? ( ) [4] [5] my PC [2] congested service [1]? [3] 1: LAN LAN ( )[1] LAN ( ) PC ( )[2] Web ( )[3] ping ( ) ( )[4] SSL ( ) ( / / )[5] 1 1.2 (multiple layered-structure)