Choisir le bon port

Bonjour,

Je voudrai savoir si il ya de quelconque obligation pour choisir un port (j'ai vu que le port 80 etait souvent utilisé,dans les source sur le site) ou est ce qu'on peut choisir n'importe quel port au hasard.
Merçi d'av pour vos réponses.

Ok merçi pour votre aide

+1 pour laurent1024 sauf que comme son pseudo l'indique pourtant tu peux prendre n'importe quel port > 1024, les autres (1024 compris étant réservés)

Un cat /etc/services sous linux liste les ports reservés comme suis :

tcpmux          1/tcp                           # TCP port service multiplexer
echo            7/tcp
echo            7/udp
discard         9/tcp           sink null
discard         9/udp           sink null
systat          11/tcp          users
daytime         13/tcp
daytime         13/udp
netstat         15/tcp
qotd            17/tcp          quote
msp             18/tcp                          # message send protocol
msp             18/udp
chargen         19/tcp          ttytst source
chargen         19/udp          ttytst source
ftp-data        20/tcp
ftp             21/tcp
fsp             21/udp          fspd
ssh             22/tcp                          # SSH Remote Login Protocol
ssh             22/udp
telnet          23/tcp
smtp            25/tcp          mail
time            37/tcp          timserver
time            37/udp          timserver
rlp             39/udp          resource        # resource location
nameserver      42/tcp          name            # IEN 116
whois           43/tcp          nicname
tacacs          49/tcp                          # Login Host Protocol (TACACS)
tacacs          49/udp
re-mail-ck      50/tcp                          # Remote Mail Checking Protocol
re-mail-ck      50/udp
domain          53/tcp          nameserver      # name-domain server
domain          53/udp          nameserver
mtp             57/tcp                          # deprecated
tacacs-ds       65/tcp                          # TACACS-Database Service
tacacs-ds       65/udp
bootps          67/tcp                          # BOOTP server
bootps          67/udp
bootpc          68/tcp                          # BOOTP client
bootpc          68/udp
tftp            69/udp
gopher          70/tcp                          # Internet Gopher
gopher          70/udp
rje             77/tcp          netrjs
finger          79/tcp
www             80/tcp          http            # WorldWideWeb HTTP
www             80/udp                          # HyperText Transfer Protocol
link            87/tcp          ttylink
kerberos        88/tcp          kerberos5 krb5 kerberos-sec     # Kerberos v5
kerberos        88/udp          kerberos5 krb5 kerberos-sec     # Kerberos v5
supdup          95/tcp
hostnames       101/tcp         hostname        # usually from sri-nic
iso-tsap        102/tcp         tsap            # part of ISODE
acr-nema        104/tcp         dicom           # Digital Imag. & Comm. 300
acr-nema        104/udp         dicom           # Digital Imag. & Comm. 300
csnet-ns        105/tcp         cso-ns          # also used by CSO name server
csnet-ns        105/udp         cso-ns
rtelnet         107/tcp                         # Remote Telnet
rtelnet         107/udp
pop2            109/tcp         postoffice pop-2 # POP version 2
pop2            109/udp         pop-2
pop3            110/tcp         pop-3           # POP version 3
pop3            110/udp         pop-3
sunrpc          111/tcp         portmapper      # RPC 4.0 portmapper
sunrpc          111/udp         portmapper
auth            113/tcp         authentication tap ident
sftp            115/tcp
uucp-path       117/tcp
nntp            119/tcp         readnews untp   # USENET News Transfer Protocol
ntp             123/tcp
ntp             123/udp                         # Network Time Protocol
pwdgen          129/tcp                         # PWDGEN service
pwdgen          129/udp                         # PWDGEN service
loc-srv         135/tcp         epmap           # Location Service
loc-srv         135/udp         epmap
netbios-ns      137/tcp                         # NETBIOS Name Service
netbios-ns      137/udp
netbios-dgm     138/tcp                         # NETBIOS Datagram Service
netbios-dgm     138/udp
netbios-ssn     139/tcp                         # NETBIOS session service
netbios-ssn     139/udp
imap2           143/tcp         imap            # Interim Mail Access P 2 and 4
imap2           143/udp         imap
snmp            161/tcp                         # Simple Net Mgmt Protocol
snmp            161/udp                         # Simple Net Mgmt Protocol
snmp-trap       162/tcp         snmptrap        # Traps for SNMP
snmp-trap       162/udp         snmptrap        # Traps for SNMP
cmip-man        163/tcp                         # ISO mgmt over IP (CMOT)
cmip-man        163/udp
cmip-agent      164/tcp
cmip-agent      164/udp
mailq           174/tcp                 # Mailer transport queue for Zmailer
mailq           174/udp                 # Mailer transport queue for Zmailer
xdmcp           177/tcp                         # X Display Mgr. Control Proto
xdmcp           177/udp
nextstep        178/tcp         NeXTStep NextStep       # NeXTStep window
nextstep        178/udp         NeXTStep NextStep       #  server
bgp             179/tcp                         # Border Gateway Protocol
bgp             179/udp
prospero        191/tcp                         # Cliff Neuman's Prospero
prospero        191/udp
irc             194/tcp                         # Internet Relay Chat
irc             194/udp
smux            199/tcp                         # SNMP Unix Multiplexer
smux            199/udp
at-rtmp         201/tcp                         # AppleTalk routing
at-rtmp         201/udp
at-nbp          202/tcp                         # AppleTalk name binding
at-nbp          202/udp
at-echo         204/tcp                         # AppleTalk echo
at-echo         204/udp
at-zis          206/tcp                         # AppleTalk zone information
at-zis          206/udp
qmtp            209/tcp                         # Quick Mail Transfer Protocol
qmtp            209/udp                         # Quick Mail Transfer Protocol
z3950           210/tcp         wais            # NISO Z39.50 database
z3950           210/udp         wais
ipx             213/tcp                         # IPX
ipx             213/udp
imap3           220/tcp                         # Interactive Mail Access
imap3           220/udp                         # Protocol v3
pawserv         345/tcp                         # Perf Analysis Workbench
pawserv         345/udp
zserv           346/tcp                         # Zebra server
zserv           346/udp
fatserv         347/tcp                         # Fatmen Server
fatserv         347/udp
rpc2portmap     369/tcp
rpc2portmap     369/udp                         # Coda portmapper
codaauth2       370/tcp
codaauth2       370/udp                         # Coda authentication server
clearcase       371/tcp         Clearcase
clearcase       371/udp         Clearcase
ulistserv       372/tcp                         # UNIX Listserv
ulistserv       372/udp
ldap            389/tcp                 # Lightweight Directory Access Protocol
ldap            389/udp
imsp            406/tcp                 # Interactive Mail Support Protocol
imsp            406/udp
https           443/tcp                         # http protocol over TLS/SSL
https           443/udp
snpp            444/tcp                         # Simple Network Paging Protocol
snpp            444/udp
microsoft-ds    445/tcp                         # Microsoft Naked CIFS
microsoft-ds    445/udp
kpasswd         464/tcp
kpasswd         464/udp
saft            487/tcp                 # Simple Asynchronous File Transfer
saft            487/udp
isakmp          500/tcp                 # IPsec - Internet Security Association
isakmp          500/udp                 #  and Key Management Protocol
rtsp            554/tcp                 # Real Time Stream Control Protocol
rtsp            554/udp                 # Real Time Stream Control Protocol
nqs             607/tcp                         # Network Queuing system
nqs             607/udp
npmp-local      610/tcp         dqs313_qmaster          # npmp-local / DQS
npmp-local      610/udp         dqs313_qmaster
npmp-gui        611/tcp         dqs313_execd            # npmp-gui / DQS
npmp-gui        611/udp         dqs313_execd
hmmp-ind        612/tcp         dqs313_intercell        # HMMP Indication / DQS
hmmp-ind        612/udp         dqs313_intercell
ipp             631/tcp                         # Internet Printing Protocol
ipp             631/udp
#
# UNIX specific services
#
exec            512/tcp
biff            512/udp         comsat
login           513/tcp
who             513/udp         whod
shell           514/tcp         cmd             # no passwords used
syslog          514/udp
printer         515/tcp         spooler         # line printer spooler
talk            517/udp
ntalk           518/udp
route           520/udp         router routed   # RIP
timed           525/udp         timeserver
tempo           526/tcp         newdate
courier         530/tcp         rpc
conference      531/tcp         chat
netnews         532/tcp         readnews
netwall         533/udp                         # for emergency broadcasts
gdomap          538/tcp                         # GNUstep distributed objects
gdomap          538/udp
uucp            540/tcp         uucpd           # uucp daemon
klogin          543/tcp                         # Kerberized `rlogin' (v5)
kshell          544/tcp         krcmd           # Kerberized `rsh' (v5)
afpovertcp      548/tcp                         # AFP over TCP
afpovertcp      548/udp
remotefs        556/tcp         rfs_server rfs  # Brunhoff remote filesystem
nntps           563/tcp         snntp           # NNTP over SSL
nntps           563/udp         snntp
submission      587/tcp                         # Submission [RFC2476]
submission      587/udp
ldaps           636/tcp                         # LDAP over SSL
ldaps           636/udp
tinc            655/tcp                         # tinc control port
tinc            655/udp
silc            706/tcp
silc            706/udp
kerberos-adm    749/tcp                         # Kerberos `kadmin' (v5)
#
webster         765/tcp                         # Network dictionary
webster         765/udp
rsync           873/tcp
rsync           873/udp
ftps-data       989/tcp                         # FTP over SSL (data)
ftps            990/tcp
telnets         992/tcp                         # Telnet over SSL
telnets         992/udp
imaps           993/tcp                         # IMAP over SSL
imaps           993/udp
ircs            994/tcp                         # IRC over SSL
ircs            994/udp
pop3s           995/tcp                         # POP-3 over SSL
pop3s           995/udp

---

TuRn3r