Protocol codes

Information and error codes for protocols (from the RFCs).

HTTP (1.1)

(From RFC 2616)

Reply code Suggested reason phrase
100 Continue
101 Switching Protocols
200 OK
201 Created
202 Accepted
203 Non-Authoritative Information
204 No Content
205 Reset Content
206 Partial Content
300 Multiple Choices
301 Moved Permanently
302 Found
303 See Other
304 Not Modified
305 Use Proxy
307 Temporary Redirect
400 Bad Request
401 Unauthorized
402 Payment Required
403 Forbidden
404 Not Found
405 Method Not Allowed
406 Not Acceptable
407 Proxy Authentication Required
408 Request Time-out
409 Conflict
410 Gone
411 Length Required
412 Precondition Failed
413 Request Entity Too Large
414 Request-URI Too Large
415 Unsupported Media Type
416 Requested range not satisfiable
417 Expectation Failed
500 Internal Server Error
501 Not Implemented
502 Bad Gateway
503 Service Unavailable
504 Gateway Time-out
505 HTTP Version not supported


(From RFC 2821)

Reply code Suggested reason phrase
211 System status, or system help reply
214 Help message
220 <domain> Service ready
221 <domain> Service closing transmission channel
250 Requested mail action okay, completed
251 User not local; will forward to <forward-path>
252 Cannot VRFY user, but will accept message and attempt delivery
354 Start mail input; end with <CRLF>.<CRLF>
421 <domain> Service not available, closing transmission channel
450 Requested mail action not taken: mailbox unavailable
451 Requested action aborted: local error in processing
452 Requested action not taken: insufficient system storage
500 Syntax error, command unrecognized
501 Syntax error in parameters or arguments
502 Command not implemented
503 Bad sequence of commands
504 Command parameter not implemented
550 Requested action not taken: mailbox unavailable
551 User not local; please try <forward-path>
552 Requested mail action aborted: exceeded storage allocation
553 Requested action not taken: mailbox name not allowed
554 Transaction failed

Port numbers

A small selection of the most commonly used port numbers

Keyword Decimal Description
ftp-data 20/tcp File Transfer [Default Data]
ftp 21/tcp File Transfer [Control]
ssh 22/tcp SSH Remote Login Protocol
smtp 25/tcp Simple Mail Transfer
nicname 43/tcp Who Is
domain 53/tcp Domain Name Server
domain 53/udp Domain Name Server
bootps 67/udp Bootstrap Protocol Server
bootpc 68/udp Bootstrap Protocol Client
http 80/tcp World Wide Web HTTP
pop3 110/tcp Post Office Protocol - Version 3
nntp 119/tcp Network News Transfer Protocol
ntp 123/udp Network Time Protocol
imap 143/tcp Internet Message Access Protocol
https 443/tcp http protocol over TLS/SSL
nntps 563/tcp nntp protocol over TLS/SSL (was snntp)
ftps-data 989/tcp ftp protocol, data, over TLS/SSL
ftps 990/tcp ftp protocol, control, over TLS/SSL
imaps 993/tcp imap4 protocol over TLS/SSL
pop3s 995/tcp pop3 protocol over TLS/SSL (was spop3)
cvspserver 2401/tcp cvspserver
mysql 3306/tcp MySQL
svn 3690/tcp Subversion
git 9418/tcp git pack transfer service