moo2
Firstly please clarify so your questions can be answered appropriately.
Do you want write access to that ibay from a remote computer connected via Internet so specified users can add or update web site content ?
Do you want password protected read access via web to that ibay so only users with a password can read the website content ?
Note you can easily update content in an ibay via local network (LAN), or if remote via a VPN connection to the sme server, are those methods satisfactory to you ?
Is it correct, that i have to allow anonymous ftp access for the ibay, if the website should be reachable without password form the internet?
No
There is no ftps option, right?
You can use sftp, but there are restrictions re how this is done. It is detailed in the manual in the ibays chapter. You need to use a suitable client (eg winscp or similar) that allows user login and issuing of commands, rather than a web browser. Search these forums on sftp as it has been answered many times. Typically you would also install the remoteuseraccess contrib to control access on a per user basis. If you search you will find the answers.
Avoid ftp as it is insecure, there are better ways you can gain access on sme server.
Please answer the earlier questions so we know what you are trying to achieve. Also if you give a plain english description of what you want to do, rather than how you wish to achieve it, this will help us advise you.
Also read this
http://wiki.contribs.org/FTP_Access_to_Ibaysbut as I say, do not use ftp if you value the data on your server and want good security, use sftp instead, refer
http://wiki.contribs.org/SME_Server:Documentation:Administration_Manual:Chapter14#Accessing_the_i-baysparticularly the section just after the Warning box.
More detailed explanations & usage instructions have been posted in these forums, so search on sftp and go back 2 or 3 or more years.
See this howto
http://wiki.contribs.org/SFTPI also searched for you, here is one of the many threads
http://forums.contribs.org/index.php/topic,45601.msg221855.html#msg221855This might also be worth reading re the pros & cons of sftp & ftps
http://www.codeguru.com/csharp/.net/net_general/internet/article.php/c14329/FTPS-vs-SFTP-What-to-Choose.htm