# Network services, Internet style
#
# Note that it is presently the policy of IANA to assign a single well-known
# port number for both TCP and UDP; hence, officially ports have two entries
# even if the protocol doesn't support UDP operations.
#
# Updated from http://www.iana.org/assignments/port-numbers and other
# sources like http://www.freebsd.org/cgi/cvsweb.cgi/src/etc/services .
# New ports will be added on request if they have been officially assigned
# by IANA and used in the real-world or are needed by a debian package.
# If you need a huge list of used numbers please install the nmap package.
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 # Domain Name Server
domain 53/udp
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
http 80/tcp www # WorldWideWeb HTTP
http 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
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
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
snmp-trap 162/tcp snmptrap # Traps for SNMP
snmp-trap 162/udp snmptrap
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
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
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
svrloc 427/tcp # Server Location
svrloc 427/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
urd 465/tcp ssmtp smtps # URL Rendesvous Directory for SSM
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
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
asf-rmcp 623/udp # ASF Remote Management and Control Protocol
qmqp 628/tcp
qmqp 628/udp
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)
dhcpv6-client 546/tcp
dhcpv6-client 546/udp
dhcpv6-server 547/tcp
dhcpv6-server 547/udp
afpovertcp 548/tcp # AFP over TCP
afpovertcp 548/udp
idfp 549/tcp
idfp 549/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 [RFC4409]
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
#
# From ``Assigned Numbers'':
#
#> The Registered Ports are not controlled by the IANA and on most systems
#> can be used by ordinary user processes or programs executed by ordinary
#> users.
#
#> Ports are used in the TCP [45,106] to name the ends of logical
#> connections which carry long term conversations. For the purpose of
#> providing services to unknown callers, a service contact port is
#> defined. This list specifies the port used by the server process as its
#> contact port. While the IANA can not control uses of these ports it
#> does register or list uses of these ports as a convienence to the
#> community.
#
socks 1080/tcp # socks proxy server
socks 1080/udp
proofd 1093/tcp
proofd 1093/udp
rootd 1094/tcp
rootd 1094/udp
openvpn 1194/tcp
openvpn 1194/udp
rmiregistry 1099/tcp # Java RMI Registry
rmiregistry 1099/udp
kazaa 1214/tcp
kazaa 1214/udp
nessus 1241/tcp # Nessus vulnerability
nessus 1241/udp # assessment scanner
lotusnote 1352/tcp lotusnotes # Lotus Note
lotusnote 1352/udp lotusnotes
ms-sql-s 1433/tcp # Microsoft SQL Server
ms-sql-s 1433/udp
ms-sql-m 1434/tcp # Microsoft SQL Monitor
ms-sql-m 1434/udp
ingreslock 1524/tcp
ingreslock 1524/udp
prospero-np 1525/tcp # Prospero non-privileged
prospero-np 1525/udp
datametrics 1645/tcp old-radius
datametrics 1645/udp old-radius
sa-msg-port 1646/tcp old-radacct
sa-msg-port 1646/udp old-radacct
kermit 1649/tcp
kermit 1649/udp
groupwise 1677/tcp
groupwise 1677/udp
l2f 1701/tcp l2tp
l2f 1701/udp l2tp
radius 1812/tcp
radius 1812/udp
radius-acct 1813/tcp radacct # Radius Accounting
radius-acct 1813/udp radacct
msnp 1863/tcp # MSN Messenger
msnp 1863/udp
unix-status 1957/tcp # remstats unix-status server
log-server 1958/tcp # remstats log server
remoteping 1959/tcp # remstats remoteping server
cisco-sccp 2000/tcp # Cisco SCCP
cisco-sccp 2000/udp
search 2010/tcp ndtp
pipe-server 2010/tcp pipe_server
nfs 2049/tcp # Network File System
nfs 2049/udp # Network File System
gnunet 2086/tcp
gnunet 2086/udp
rtcm-sc104 2101/tcp # RTCM SC-104 IANA 1/29/99
rtcm-sc104 2101/udp
gsigatekeeper 2119/tcp
gsigatekeeper 2119/udp
gris 2135/tcp # Grid Resource Information Server
gris 2135/udp
cvspserver 2401/tcp # CVS client/server operations
cvspserver 2401/udp
venus 2430/tcp # codacon port
venus 2430/udp # Venus callback/wbc interface
venus-se 2431/tcp # tcp side effects
venus-se 2431/udp # udp sftp side effect
codasrv 2432/tcp # not used
codasrv 2432/udp # server port
codasrv-se 2433/tcp # tcp side effects
codasrv-se 2433/udp # udp sftp side effect
mon 2583/tcp # MON traps
mon 2583/udp
dict 2628/tcp # Dictionary server
dict 2628/udp
f5-globalsite 2792/tcp
f5-globalsite 2792/udp
gsiftp 2811/tcp
gsiftp 2811/udp
gpsd 2947/tcp
gpsd 2947/udp
gds-db 3050/tcp gds_db # InterBase server
gds-db 3050/udp gds_db
icpv2 3130/tcp icp # Internet Cache Protocol
icpv2 3130/udp icp
iscsi-target 3260/tcp
mysql 3306/tcp
mysql 3306/udp
nut 3493/tcp # Network UPS Tools
nut 3493/udp
distcc 3632/tcp # distributed compiler
distcc 3632/udp
daap 3689/tcp # Digital Audio Access Protocol
daap 3689/udp
svn 3690/tcp subversion # Subversion protocol
svn 3690/udp subversion
suucp 4031/tcp # UUCP over SSL
suucp 4031/udp
sysrqd 4094/tcp # sysrq daemon
sysrqd 4094/udp
sieve 4190/tcp # ManageSieve Protocol
epmd 4369/tcp # Erlang Port Mapper Daemon
epmd 4369/udp
remctl 4373/tcp # Remote Authenticated Command Service
remctl 4373/udp
f5-iquery 4353/tcp # F5 iQuery
f5-iquery 4353/udp
ipsec-nat-t 4500/udp # IPsec NAT-Traversal [RFC3947]
iax 4569/tcp # Inter-Asterisk eXchange
iax 4569/udp
mtn 4691/tcp # monotone Netsync Protocol
mtn 4691/udp
radmin-port 4899/tcp # RAdmin Port
radmin-port 4899/udp
rfe 5002/udp # Radio Free Ethernet
rfe 5002/tcp
mmcc 5050/tcp # multimedia conference control tool (Yahoo IM)
mmcc 5050/udp
sip 5060/tcp # Session Initiation Protocol
sip 5060/udp
sip-tls 5061/tcp
sip-tls 5061/udp
aol 5190/tcp # AIM
aol 5190/udp
xmpp-client 5222/tcp jabber-client # Jabber Client Connection
xmpp-client 5222/udp jabber-client
xmpp-server 5269/tcp jabber-server # Jabber Server Connection
xmpp-server 5269/udp jabber-server
cfengine 5308/tcp
cfengine 5308/udp
mdns 5353/tcp # Multicast DNS
mdns 5353/udp
postgresql 5432/tcp postgres # PostgreSQL Database
postgresql 5432/udp postgres
freeciv 5556/tcp rptp # Freeciv gameplay
freeciv 5556/udp
amqps 5671/tcp # AMQP protocol over TLS/SSL
amqp 5672/tcp
amqp 5672/udp
amqp 5672/sctp
ggz 5688/tcp # GGZ Gaming Zone
ggz 5688/udp
x11 6000/tcp x11-0 # X Window System
x11 6000/udp x11-0
x11-1 6001/tcp
x11-1 6001/udp
x11-2 6002/tcp
x11-2 6002/udp
x11-3 6003/tcp
x11-3 6003/udp
x11-4 6004/tcp
x11-4 6004/udp
x11-5 6005/tcp
x11-5 6005/udp
x11-6 6006/tcp
x11-6 6006/udp
x11-7 6007/tcp
x11-7 6007/udp
gnutella-svc 6346/tcp # gnutella
gnutella-svc 6346/udp
gnutella-rtr 6347/tcp # gnutella
gnutella-rtr 6347/udp
sge-qmaster 6444/tcp sge_qmaster # Grid Engine Qmaster Service
sge-qmaster 6444/udp sge_qmaster
sge-execd 6445/tcp sge_execd # Grid Engine Execution Service
sge-execd 6445/udp sge_execd
mysql-proxy 6446/tcp # MySQL Proxy
mysql-proxy 6446/udp
afs3-fileserver 7000/tcp bbs # file server itself
afs3-fileserver 7000/udp bbs
afs3-callback 7001/tcp # callbacks to cache managers
afs3-callback 7001/udp
afs3-prserver 7002/tcp # users & groups database
afs3-prserver 7002/udp
afs3-vlserver 7003/tcp # volume location database
afs3-vlserver 7003/udp
afs3-kaserver 7004/tcp # AFS/Kerberos authentication
afs3-kaserver 7004/udp
afs3-volser 7005/tcp # volume managment server
afs3-volser 7005/udp
afs3-errors 7006/tcp # error interpretation service
afs3-errors 7006/udp
afs3-bos 7007/tcp # basic overseer process
afs3-bos 7007/udp
afs3-update 7008/tcp # server-to-server updater
afs3-update 7008/udp
afs3-rmtsys 7009/tcp # remote cache manager service
afs3-rmtsys 7009/udp
font-service 7100/tcp xfs # X Font Service
font-service 7100/udp xfs
http-alt 8080/tcp webcache # WWW caching service
http-alt 8080/udp
bacula-dir 9101/tcp # Bacula Director
bacula-dir 9101/udp
bacula-fd 9102/tcp # Bacula File Daemon
bacula-fd 9102/udp
bacula-sd 9103/tcp # Bacula Storage Daemon
bacula-sd 9103/udp
xmms2 9667/tcp # Cross-platform Music Multiplexing System
xmms2 9667/udp
nbd 10809/tcp # Linux Network Block Device
zabbix-agent 10050/tcp # Zabbix Agent
zabbix-agent 10050/udp
zabbix-trapper 10051/tcp # Zabbix Trapper
zabbix-trapper 10051/udp
amanda 10080/tcp # amanda backup services
amanda 10080/udp
dicom 11112/tcp
hkp 11371/tcp # OpenPGP HTTP Keyserver
hkp 11371/udp
bprd 13720/tcp # VERITAS NetBackup
bprd 13720/udp
bpdbm 13721/tcp # VERITAS NetBackup
bpdbm 13721/udp
bpjava-msvc 13722/tcp # BP Java MSVC Protocol
bpjava-msvc 13722/udp
vnetd 13724/tcp # Veritas Network Utility
vnetd 13724/udp
bpcd 13782/tcp # VERITAS NetBackup
bpcd 13782/udp
vopied 13783/tcp # VERITAS NetBackup
vopied 13783/udp
db-lsp 17500/tcp # Dropbox LanSync Protocol
dcap 22125/tcp # dCache Access Protocol
gsidcap 22128/tcp # GSI dCache Access Protocol
wnn6 22273/tcp # wnn6
wnn6 22273/udp
#
# Datagram Delivery Protocol services
#
rtmp 1/ddp # Routing Table Maintenance Protocol
nbp 2/ddp # Name Binding Protocol
echo 4/ddp # AppleTalk Echo Protocol
zip 6/ddp # Zone Information Protocol
#=========================================================================
# The remaining port numbers are not as allocated by IANA.
#=========================================================================
# Kerberos (Project Athena/MIT) services
# Note that these are for Kerberos v4, and are unofficial. Sites running
# v4 should uncomment these and comment out the v5 entries above.
#
kerberos4 750/udp kerberos-iv kdc # Kerberos (server)
kerberos4 750/tcp kerberos-iv kdc
kerberos-master 751/udp kerberos_master # Kerberos authentication
kerberos-master 751/tcp
passwd-server 752/udp passwd_server # Kerberos passwd server
krb-prop 754/tcp krb_prop krb5_prop hprop # Kerberos slave propagation
krbupdate 760/tcp kreg # Kerberos registration
swat 901/tcp # swat
kpop 1109/tcp # Pop with Kerberos
knetd 2053/tcp # Kerberos de-multiplexor
zephyr-srv 2102/udp # Zephyr server
zephyr-clt 2103/udp # Zephyr serv-hm connection
zephyr-hm 2104/udp # Zephyr hostmanager
eklogin 2105/tcp # Kerberos encrypted rlogin
# Hmmm. Are we using Kv4 or Kv5 now? Worrying.
# The following is probably Kerberos v5 --- ajt@debian.org (11/02/2000)
kx 2111/tcp # X over Kerberos
iprop 2121/tcp # incremental propagation
#
# Unofficial but necessary (for NetBSD) services
#
supfilesrv 871/tcp # SUP server
supfiledbg 1127/tcp # SUP debugging
#
# Services added for the Debian GNU/Linux distribution
#
linuxconf 98/tcp # LinuxConf
poppassd 106/tcp # Eudora
poppassd 106/udp
moira-db 775/tcp moira_db # Moira database
moira-update 777/tcp moira_update # Moira update protocol
moira-ureg 779/udp moira_ureg # Moira user registration
spamd 783/tcp # spamassassin daemon
omirr 808/tcp omirrd # online mirror
omirr 808/udp omirrd
customs 1001/tcp # pmake customs server
customs 1001/udp
skkserv 1178/tcp # skk jisho server port
predict 1210/udp # predict -- satellite tracking
rmtcfg 1236/tcp # Gracilis Packeten remote config server
wipld 1300/tcp # Wipl network monitor
xtel 1313/tcp # french minitel
xtelw 1314/tcp # french minitel
support 1529/tcp # GNATS
cfinger 2003/tcp # GNU Finger
frox 2121/tcp # frox: caching ftp proxy
ninstall 2150/tcp # ninstall service
ninstall 2150/udp
zebrasrv 2600/tcp # zebra service
zebra 2601/tcp # zebra vty
ripd 2602/tcp # ripd vty (zebra)
ripngd 2603/tcp # ripngd vty (zebra)
ospfd 2604/tcp # ospfd vty (zebra)
bgpd 2605/tcp # bgpd vty (zebra)
ospf6d 2606/tcp # ospf6d vty (zebra)
ospfapi 2607/tcp # OSPF-API
isisd 2608/tcp # ISISd vty (zebra)
afbackup 2988/tcp # Afbackup system
afbackup 2988/udp
afmbackup 2989/tcp # Afmbackup system
afmbackup 2989/udp
xtell 4224/tcp # xtell server
fax 4557/tcp # FAX transmission service (old)
hylafax 4559/tcp # HylaFAX client-server protocol (new)
distmp3 4600/tcp # distmp3host daemon
munin 4949/tcp lrrd # Munin
enbd-cstatd 5051/tcp # ENBD client statd
enbd-sstatd 5052/tcp # ENBD server statd
pcrd 5151/tcp # PCR-1000 Daemon
noclog 5354/tcp # noclogd with TCP (nocol)
noclog 5354/udp # noclogd with UDP (nocol)
hostmon 5355/tcp # hostmon uses TCP (nocol)
hostmon 5355/udp # hostmon uses UDP (nocol)
rplay 5555/udp # RPlay audio service
nrpe 5666/tcp # Nagios Remote Plugin Executor
nsca 5667/tcp # Nagios Agent - NSCA
mrtd 5674/tcp # MRT Routing Daemon
bgpsim 5675/tcp # MRT Routing Simulator
canna 5680/tcp # cannaserver
syslog-tls 6514/tcp # Syslog over TLS [RFC5425]
sane-port 6566/tcp sane saned # SANE network scanner daemon
ircd 6667/tcp # Internet Relay Chat
zope-ftp 8021/tcp # zope management by ftp
tproxy 8081/tcp # Transparent Proxy
omniorb 8088/tcp # OmniORB
omniorb 8088/udp
clc-build-daemon 8990/tcp # Common lisp build daemon
xinetd 9098/tcp
mandelspawn 9359/udp mandelbrot # network mandelbrot
git 9418/tcp # Git Version Control System
zope 9673/tcp # zope server
webmin 10000/tcp
kamanda 10081/tcp # amanda backup services (Kerberos)
kamanda 10081/udp
amandaidx 10082/tcp # amanda backup services
amidxtape 10083/tcp # amanda backup services
smsqp 11201/tcp # Alamin SMS gateway
smsqp 11201/udp
xpilot 15345/tcp # XPilot Contact Port
xpilot 15345/udp
sgi-cmsd 17001/udp # Cluster membership services daemon
sgi-crsd 17002/udp
sgi-gcd 17003/udp # SGI Group membership daemon
sgi-cad 17004/tcp # Cluster Admin daemon
isdnlog 20011/tcp # isdn logging system
isdnlog 20011/udp
vboxd 20012/tcp # voice box system
vboxd 20012/udp
binkp 24554/tcp # binkp fidonet protocol
asp 27374/tcp # Address Search Protocol
asp 27374/udp
csync2 30865/tcp # cluster synchronization tool
dircproxy 57000/tcp # Detachable IRC Proxy
tfido 60177/tcp # fidonet EMSI over telnet
fido 60179/tcp # fidonet EMSI over TCP
# Local services
Comments
Post a Comment