ftp - special characters in the user name allowed?

Posted on 2004-03-23
Last Modified: 2013-12-23
user has a name   -   is this legal?  When trying to ftp through our firewall, it is rejected even though this is their valid user id.
Question by:dcurylo
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ID: 10660358
Do you use real FTP client or a web browser ???
Usernames of any kind without whitespaces are quite OK, interpretation varies form server to server.

Author Comment

ID: 10660942
So there is no standard requirements?  It is a real ftp client.
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Expert Comment

ID: 10663160
Well, is not a valid email address, so a remote anonymous FTP server might well reject the session.
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Expert Comment

ID: 10664678
RFC1123 denotes some standard of a kind, @ is not a telnet-special character (but it can confuse URL parser which prefers ftp://user:password@host)

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ID: 10829427  is used in some cases of mail redirection, like in Lotus Notes.
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ID: 10829454
I forgot to mention that in this case, the address is evaluated first
  then (from internally)
  then (from company.intranet internal servers)
  then (from internalservice, likely to be a mail server, posting locally to johnford)

If it can make it more clear.
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ID: 10830014
Never seen FTP software named Lotus Notes
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ID: 10831702
About ftp, for info, proxy ftps have a similar syntax for username
where domain is the actual host to connect to, using user xxx
I guess in the case of xxx@yyy@domain, xxx@yyy would be interpreted as a user name, for a proxy ftp.

In your case the firewall could prevent the host bouncing :
   user ---> your-ftp-server ---->
- if your ftp server understands the proxy ftp syntax, it will try to connect to, using xxx@yyy as user name
- if your ftp server is not supposed to authorize this host bouncing, it's fortunate the firewall prevents the connection to happen.

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