FTP Further Info & Troubleshooting

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Passive Port Range

Passive ports are used to allow multiple FTP connctions connections   by moving open FTP connections from port 21 to a port specified in the passive port range (40,000-40,100 is the standard UKFastANS passive port range ). See relevant panel/cli doc pages for specific info on how the passive port range can be set.

Calculating FTP that's being used for connection:

A telltale sign of FTP port issues is encountering a connection refused error when the FTP connection attempt enters passive mode. Typically this error will be outputted as follows:

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Checking/Changing Passive Ports:

CommonWe Passivecan use the numbers included in the error to calculate the port which the FTP Error:

connection

Canhas connectattempted butto can't retrieve directory listing:  use.

80,244,185,220,156,149  

First 4 numbers are the server IP,   

Multiply 5th number by 256 = x  

X+6th number = passive port which is being used  

156x256=39936+149=40085  

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none-panelled:

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cPanel:

cPanel will use either ProFTP or PureFTP:

PureFTP:

 /var/cpanel/conf/pureftpd/local 

Once updated, the FTP service needs to be restarted with the following command: 

/usr/local/cpanel/scripts/setupftpserver pure-ftpd --force  

ProFTP:

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Plesk:

Check in /etc/proftpd.d/passive ports folder