Merci de ta réponse.

Je n'ai malheureusement pas de message d'erreur, juste debian:/# /etc/init.d/mysql start
Starting MySQL database server: mysqld . . . . . . . . . . . . . . failed!

Pour la 1ère commande, j'obtiens root 2500 0.0 0.1 2800 1344 ? S 08:58 0:00 /bin/sh /usr/bin/mysqld_safe
mysql 2558 0.0 1.9 127224 17744 ? Sl 08:58 0:00 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/var/run/mysqld/mysqld.pid --skip-external-locking --port=3306 --socket=/var/run/mysqld/mysqld.sock
root 2559 0.0 0.0 1680 552 ? S 08:58 0:00 logger -p daemon.err -t mysqld_safe -i -t mysqld
root 13314 0.0 0.1 4348 1308 pts/0 S 10:32 0:00 /bin/sh /usr/bin/mysqld_safe
mysql 13351 0.0 1.0 74804 9756 pts/0 Sl 10:32 0:00 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/var/run/mysqld/mysqld.pid --skip-external-locking --port=3306 --socket=/var/run/mysqld/mysqld.sock
root 13352 0.0 0.0 3404 616 pts/0 S 10:32 0:00 logger -p daemon.err -t mysqld_safe -i -t mysqld
root 13530 0.0 0.0 3560 760 pts/0 R+ 10:33 0:00 grep mysql

Quant au nestat, cela m'affiche Connexions Internet actives (seulement serveurs)
Proto Recv-Q Send-Q Adresse locale Adresse distante Etat PID/Program name
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN 2558/mysqld
tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 2155/portmap
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 3540/apache2
tcp 0 0 0.0.0.0:47925 0.0.0.0:* LISTEN 7093/rpc.statd
tcp 0 0 127.0.0.1:8118 0.0.0.0:* LISTEN 3247/privoxy
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 4117/cupsd
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 3081/exim4
tcp 0 0 127.0.0.1:9050 0.0.0.0:* LISTEN 3253/tor
udp 0 0 0.0.0.0:32769 0.0.0.0:* 3301/avahi-daemon:
udp 0 0 0.0.0.0:909 0.0.0.0:* 7093/rpc.statd
udp 0 0 0.0.0.0:68 0.0.0.0:* 3421/dhclient
udp 0 0 0.0.0.0:68 0.0.0.0:* 2491/dhclient3
udp 0 0 0.0.0.0:32839 0.0.0.0:* 7093/rpc.statd
udp 0 0 0.0.0.0:5353 0.0.0.0:* 3301/avahi-daemon:
udp 0 0 0.0.0.0:111 0.0.0.0:* 2155/portmap
udp 0 0 0.0.0.0:631 0.0.0.0:* 4117/cupsd
Sockets du domaine UNIX actives(seulement serveurs)
Proto RefCpt Indicatrs Type Etat I-Node PID/Program name Chemin
unix 2 [ ACC ] STREAM LISTENING 15708 4117/cupsd /var/run/cups/cups.sock
unix 2 [ ACC ] STREAM LISTENING 7028 2558/mysqld /var/run/mysqld/mysqld.sock
unix 2 [ ACC ] STREAM LISTENING 7482 2828/dbus-daemon /var/run/dbus/system_bus_socket
unix 2 [ ACC ] STREAM LISTENING 7204 2680/acpid /var/run/acpid.socket
unix 2 [ ACC ] STREAM LISTENING 122310 13272/gconfd-2 /tmp/orbit-root/linc-33d8-0-1192c10d5d0e7
unix 2 [ ACC ] STREAM LISTENING 26394 4684/gnome-terminal /tmp/orbit-root/linc-124c-0-2375a62684740
unix 2 [ ACC ] STREAM LISTENING 26417 4688/bonobo-activat /tmp/orbit-root/linc-1250-0-5d272373ed9b5
unix 2 [ ACC ] STREAM LISTENING 8212 3301/avahi-daemon: /var/run/avahi-daemon/socket
unix 2 [ ACC ] STREAM LISTENING 8240 3316/hald @/var/run/hald/dbus-pQQGNQFjNW
unix 2 [ ACC ] STREAM LISTENING 9078 3419/X /tmp/.X11-unix/X0
unix 2 [ ACC ] STREAM LISTENING 8243 3316/hald @/var/run/hald/dbus-YDH1iHXGVb
unix 2 [ ACC ] STREAM LISTENING 9655 3648/gnome-keyring- /tmp/keyring-5lgXQD/socket
unix 2 [ ACC ] STREAM LISTENING 9597 3643/dbus-daemon @/tmp/dbus-7qRmeFew36
unix 2 [ ACC ] STREAM LISTENING 9615 3645/gconfd-2 /tmp/orbit-renolipus/linc-e3d-0-282c2630e4274
unix 2 [ ACC ] STREAM LISTENING 9625 3591/gnome-session /tmp/orbit-renolipus/linc-e07-0-1396d9bfff95
unix 2 [ ACC ] STREAM LISTENING 9674 3650/gnome-settings /tmp/orbit-renolipus/linc-e42-0-ad3b14bcd300
unix 2 [ ACC ] STREAM LISTENING 9734 3662/gnome-panel /tmp/orbit-renolipus/linc-e4e-0-5662fa899f49
unix 2 [ ACC ] STREAM LISTENING 9770 3659/metacity /tmp/orbit-renolipus/linc-e4b-0-56195d7ecc50e
unix 2 [ ACC ] STREAM LISTENING 9788 3664/nautilus /tmp/orbit-renolipus/linc-e50-0-774d58782d6fb
unix 2 [ ACC ] STREAM LISTENING 9815 3673/gnome-vfs-daem /tmp/orbit-renolipus/linc-e59-0-7c4f421781a82
unix 2 [ ACC ] STREAM LISTENING 9835 3675/bluetooth-appl /tmp/orbit-renolipus/linc-e5b-0-1f3663c38d94e
unix 2 [ ACC ] STREAM LISTENING 9866 3681/update-notifie /tmp/orbit-renolipus/linc-e61-0-774d5878eaa7d
unix 2 [ ACC ] STREAM LISTENING 9874 3686/gnome-volume-m /tmp/orbit-renolipus/linc-e63-0-774d5878f03b0
unix 2 [ ACC ] STREAM LISTENING 9900 3684/nm-applet /tmp/orbit-renolipus/linc-e64-0-59387f48207aa
unix 2 [ ACC ] STREAM LISTENING 9916 3687/gnome-power-ma /tmp/orbit-renolipus/linc-e62-0-59387f4852fe5
unix 2 [ ACC ] STREAM LISTENING 9029 3407/gdm /tmp/.gdm_socket
unix 2 [ ACC ] STREAM LISTENING 9925 3670/bonobo-activat /tmp/orbit-renolipus/linc-e56-0-26ee64225e4b8
unix 2 [ ACC ] STREAM LISTENING 9974 3713/mapping-daemon /tmp/mapping-renolipus
unix 2 [ ACC ] STREAM LISTENING 9948 3685/gnome-cups-ico /tmp/orbit-renolipus/linc-e65-0-59387f4896da2
unix 2 [ ACC ] STREAM LISTENING 54156 10995/gnome-system- /tmp/gnome-system-monitor.renolipus.3134918617
unix 2 [ ACC ] STREAM LISTENING 9996 3718/geyes_applet2 /tmp/orbit-renolipus/linc-e86-0-7d0ccfcbd2ada
unix 2 [ ACC ] STREAM LISTENING 82370 12352/gedit /tmp/gedit.renolipus.1755406317
unix 2 [ ACC ] STREAM LISTENING 10049 3723/multiload-appl /tmp/orbit-renolipus/linc-e8b-0-512aa9b8e481c
unix 2 [ ACC ] STREAM LISTENING 10503 3752/icedove-bin /tmp/orbit-renolipus/linc-ea8-0-52a17ae0bccd2
unix 2 [ ACC ] STREAM LISTENING 10524 3771/gnome-screensa /tmp/orbit-renolipus/linc-eb9-0-35daacbe4c8ad
unix 2 [ ACC ] STREAM LISTENING 10948 3792/firefox-bin /tmp/orbit-renolipus/linc-ed0-0-307949bd6c15f
unix 2 [ ACC ] STREAM LISTENING 16188 4258/gksu /tmp/orbit-renolipus/linc-10a2-0-3675c359c7c88
unix 2 [ ACC ] STREAM LISTENING 26335 4673/gksu /tmp/orbit-renolipus/linc-1241-0-7147242b4ac0a
unix 2 [ ACC ] STREAM LISTENING 47887 6710/notification-d /tmp/orbit-renolipus/linc-1a36-0-3e914ddb1a5a1
unix 2 [ ACC ] STREAM LISTENING 54163 10995/gnome-system- /tmp/orbit-renolipus/linc-2af3-0-50bccb3099c9a
unix 2 [ ACC ] STREAM LISTENING 60169 11140/gksu /tmp/orbit-renolipus/linc-2b84-0-2221e1f2e5d5c
unix 2 [ ACC ] STREAM LISTENING 82366 12352/gedit /tmp/orbit-renolipus/linc-3040-0-bbce758e1599
unix 2 [ ACC ] STREAM LISTENING 9646 3591/gnome-session /tmp/.ICE-unix/3591
unix 2 [ ACC ] STREAM LISTENING 9586 3639/ssh-agent /tmp/ssh-uqVtFK3591/agent.3591
Voilà.