1) On utilise la commande ncat -ul 50000 sur un premier terminal. sur un autre terminal on utilise la commande ss -lnu [solar@salle231-04 TP14]$ ss -lun State Recv-Q Send-Q Local Address:Port Peer Address:Port UNCONN 0 0 0.0.0.0:5353 0.0.0.0:* UNCONN 0 0 0.0.0.0:5355 0.0.0.0:* UNCONN 0 0 127.0.0.54:53 0.0.0.0:* UNCONN 0 0 127.0.0.53%lo:53 0.0.0.0:* UNCONN 0 0 172.16.2.91%eno1:68 0.0.0.0:* UNCONN 0 0 172.17.255.255:137 0.0.0.0:* UNCONN 0 0 172.17.0.1:137 0.0.0.0:* UNCONN 0 0 172.16.255.255:137 0.0.0.0:* UNCONN 0 0 172.16.2.91:137 0.0.0.0:* UNCONN 0 0 0.0.0.0:137 0.0.0.0:* UNCONN 0 0 172.17.255.255:138 0.0.0.0:* UNCONN 0 0 172.17.0.1:138 0.0.0.0:* UNCONN 0 0 172.16.255.255:138 0.0.0.0:* UNCONN 0 0 172.16.2.91:138 0.0.0.0:* UNCONN 0 0 0.0.0.0:138 0.0.0.0:* UNCONN 0 0 0.0.0.0:50000 0.0.0.0:* UNCONN 0 0 [::]:5353 [::]:* UNCONN 0 0 [::]:5355 [::]:* UNCONN 0 0 [fe80::e654:e8ff:fea1:a2e8]%eno1:546 [::]:* UNCONN 0 0 [::]:50000 [::]:* 2) dd if=/dev/urandom of=ft-file.dat bs=1024 count=9 9+0 records in 9+0 records out 9216 bytes (9.2 kB, 9.0 KiB) copied, 0.0083619 s, 1.1 MB/s ls -lh ft-file.dat -rw-r--r-- 1 solar students23 9.0K Mar 12 14:52 ft-file.dat 3) ncat -lu 50000 > resultat ncat 192.16.2.91 < ft-file.dat a la fin dans resultat on a la même chose que tu sur le fichier ft-file.dat -rw-r--r-- 1 solar info-etu-but-2024 9216 Feb 11 17:06 resultat 4. tcpdump -tn "tcp and port 50000 and not arp" II) 1) which traceroute which: no traceroute in (/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/opt/android-sdk/platform-tools:/opt/android-sdk/tools:/opt/android-sdk/tools/bin:/usr/lib/jvm/default/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl) which tracepath /usr/bin/tracepath cela signifie que tracepath existe et non traceroute 2) tcpdump -vvv -i eno1 -f "host 172.16.3.198 and not tcp and not udp and not arp" -w tracepath-trace.txt tracepath 8.8.8.8 tcpdump -r tracepath-trace.txt 3) -n permet d'afficher les ip numériques 4) tcpdump -r tracepath-trace.txt |sed '/UDP.*$/a \\' a) tcpdump: verbose output suppressed, use -v[v]... for full protocol decode listening on eno1, link-type EN10MB (Ethernet), snapshot length 262144 bytes ^C 0 packets captured 0 packets received by filter 0 packets dropped by kernel b) tcpdump: verbose output suppressed, use -v[v]... for full protocol decode listening on eno1, link-type EN10MB (Ethernet), snapshot length 262144 bytes ^C 0 packets captured 0 packets received by filter 0 packets dropped by kernel c) tcpdump: verbose output suppressed, use -v[v]... for full protocol decode listening on eno1, link-type EN10MB (Ethernet), snapshot length 262144 bytes ^C 0 packets captured 0 packets received by filter 0 packets dropped by kernel 6) serveur : -terminal 1: ncat -ul 50000 -terminal 2: tcpdump -i eno1 "udp and port 50000" tcpdump: verbose output suppressed, use -v[v]... for full protocol decode listening on eno1, link-type EN10MB (Ethernet), snapshot length 262144 bytes 16:40:07.467945 IP salle229-02.iut-fbleau.fr.52428 > salle229-01.iut-fbleau.fr.50000: UDP, length 8192 16:40:07.468060 IP salle229-02.iut-fbleau.fr.52428 > salle229-01.iut-fbleau.fr.50000: UDP, length 1024 Client : terminal 1: tcpdump -i eno1 "udp and port 50000" terminal 2: ncat -u [ip] 500000 < ft-file.dat 7) Il y a 2 paquet, un de 8192 et un autre de 1024. II)