FTP “Error: Server returned unroutable private IP address in PASV reply”


If you run a firewall on your Linux server and want to use passive FTP connections, you have to define the passive port range in pure-ftpd and your firewall to ensure that the connections don’t get blocked. The following example is for pure-ftpd on Debian or Ubuntu Linux and ISPConfig 3.


Set Passive Port Range in PureFTPD

1) Configure pure-ftpd


echo “40110 40210” > /etc/pure-ftpd/conf/PassivePortRange

service pure-ftpd-mysql restart

2) Configure the firewall. If you use ISPConfig 3 on my server to configure the bastille firewall, you can add the nescessera port range in the ISPConfig firewall settings.


Change the list of Open TCP ports from:






and then click on “Save”.


Set Passive IP in PureFTPD

Setting a passive IP in FTP might be necessary when your server is located behind a NAT router. You will get an error like “Error: Server returned unroutable private IP address in PASV reply” from your FTP client in such a case.


To set a passive IP address, run this command:


echo “” > /etc/pure-ftpd/conf/ForcePassiveIP

Replace with the External IP address that clients shall use to connect to the FTP server. Then restart pureFTPD:


service pure-ftpd-mysql restart






Kon Belieu


Kon@cxit.com   |  513-575-3500

4440 Lake Forest Dr., Suite 102B, Cincinnati, OH  45242



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