[mr_F_2]

this *should* work.

note: requires registered version

find and edit / add these sections, text in bold you can change to; suit your needs

[FTP_LAN_INTERNAL]
Host = 192.168.0.1
Ports = 1024-2048
Random = True
;Global_Inbound_Bandwidth = 10000
;Global_Outbound_Bandwidth = 10000
;Client_Inbound_Bandwidth = 100 [*registered version*]
;Client_Outbound_Bandwidth = 50 [*registered version*]
;Bind =

[INTERNET]
Host = 0.0.0.0
Ports = 1024-2048
Random = True
Global_Inbound_Bandwidth = 50
Global_Outbound_Bandwidth = 50
;Client_Inbound_Bandwidth = 100 [*registered version*]
;Client_Outbound_Bandwidth = 50 [*registered version*]
;Bind =

[FTP_Service]
Type = FTP
Device_Name = INTERNET
Port = 21
Description = My internet FTP service
User_Limit = 10
Allowed_Users = *
Messages = ..\text\ftp

[internal_FTP_Service]
Type = FTP
Device_Name = FTP_LAN_INTERNAL
Port = 22
Description = My internal FTP service
User_Limit = 10
Allowed_Users = i !*
Messages = ..\text\ftp

...

Active_Services = FTP_Service internal_FTP_Service


now if you give a user flag +i he is allowed to use internal ip server, otherwise he isn't. and likewise you could make a setting to prevent internal lan users unable to login via the internet ip.

i hope that helps