MultiCom Technical Support

[Support]

If there are 2 Multicom NAT's between an ftp client and server the client can only login in but not establish data transfers (as seen by attempting to use the command ls, get or put). Passive or Active communication will fail. Below is a simple version of the connection having a problem.

ftp client - Pocket NAT - Internet - Pocket NAT - ftp server

There are 2 workarounds:

1. When one of the NAT's are turned off full access is possible.
   
2. Use NAT but also use "IP SiteAddr x.x.x.x mapto y.y.y.y" where x.x.x.x is the public or NAT IP address and y.y.y.y is the IP address of the server in the LAN.

Please note that solution #2 will open a hole in the NAT firewall. If you wish to secure this IP address you will need to use the filtering rules of your MultiCom router.