FTPMonitor / Guides / FTP timeout during transfer

FTP timeout during transfer

Why FTP transfers timeout and how to fix idle timeout or firewall issues.

Diagnose this automatically

Test whether the server allows directory listing with valid credentials.

terminal

npx ftpmonitor check --protocol ftp --host ftp.example.com --port 21 --username user --password pass --path /incoming

Shareable output

terminal

npx ftpmonitor check --protocol ftp --host ftp.example.com --port 21 --username user --password pass --path /incoming --format slack --copy

FTP transfers may timeout if the data channel is interrupted or idle time limits are reached.

Common causes

FTP passive mode firewall issues — Why FTP PASV fails behind firewalls/NAT and how to configure passive ports correctly.
FTP data connection failed — Why FTP data connections fail and how to troubleshoot passive and active data channel issues.
FTP directory listing timeout — Why FTP directory listings hang or timeout and how to resolve passive mode firewall problems.
FTP passive mode not working — Why FTP passive mode fails and how to configure passive ports and NAT correctly.
FTP EPSV error — Understanding FTP EPSV errors and how to resolve extended passive mode problems.
FTP transfer stalls — Why FTP transfers stall mid-transfer and how to troubleshoot data channel issues.