Common operational misconceptions
mysidia at gmail.com
Mon Feb 20 01:09:49 UTC 2012
On Sun, Feb 19, 2012 at 6:24 PM, Owen DeLong <owen at delong.com> wrote:
> I have 15 FTP servers and 22 web servers behind it.
> I want people to be able to go to ftp://<hostname> and/or http://<hostname> for each of them.
For HTTP; You put a device on that one IP that will accept each TCP
connection, await the SNI or Host header from the client, and then
make/forward the connection to a proper server for that hostname.
The public IP address belongs to the FTP/HTTP "service" instead of
belonging to a server.
For FTP, send to a desired FTP server based on the login username or
otherwise make a SRV record for the _ftp service for each hostname,
and set aside a TCP port for each FTP service's control connection.
The ftp://[email protected]<hostname> approach or the
ftp://[email protected]<basehostname>/<hostname>/ is probably more convenient
than ftp://<hostname>:<1234>, since many clients do not support SRV
The problem is with the FTP protocol not supporting virtual hosting,
though; this missing FTP feature is not a NAT problem per se.
The VHOST problem was solved with HTTP a long time ago.
It's just that FTP is a lot less popular / fell into some disuse, so
the deficiency (lack of virtual hosting support) was never
corrected -- and the protocol hasn't had a single update in a long
So you'll have to have a workaround to do 15 FTP servers with one
global IP, because your circumstance is so unusual, that's just
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