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ProtocolCodes
451
FTP

451 Local Error

Requested action aborted: local error in processing. The server encountered an unexpected error while trying to complete the command.

On this page

When You See This Code

When the server has an internal issue like a disk I/O error, memory shortage, or filesystem problem during command processing.

How to Fix

Retry the command. If the error persists, contact the server administrator to check disk health, available memory, and server logs.

Specification

View RFC / Specification →

Compare With

110 Restart Marker Reply 120 Service Ready Soon 125 Data Connection Open 150 File Status OK 200 Command OK 202 Command Superfluous 211 System Status 212 Directory Status 213 File Status 214 Help Message 215 System Type 220 Service Ready

Guides

FTP Reply Codes: Understanding File Transfer Responses DNS & Networking
TCP Three-Way Handshake and Connection Lifecycle DNS & Networking
Essential Network Debugging Tools: ping, traceroute, mtr, and tcpdump DNS & Networking
RFC 959: FTP Protocol Deep Dive Protocol Deep Dives
TLS 1.3: Faster, Simpler, More Secure Protocol Deep Dives
Migrating from FTP to SFTP: A Complete Transition Guide Migration & Upgrades
HTTP Access Log Management: Rotation, Parsing, and Analysis Production Infrastructure

Debugging Scenarios

426 Connection Closed — Transfer Aborted Mid-File Intermediate

Glossary

Status Code TLS Handshake TCP/IP Three-Way Handshake Port Number Firewall Proxy Server (Forward Proxy) Socket Request-Response Model RFC (Request for Comments) Connection-Oriented Half-Duplex Text vs Binary Protocol FTP Active Mode FTP Passive Mode FTP Control Channel FTP Data Channel SFTP (SSH File Transfer Protocol) FTPS (FTP Secure) FTP Reply Code FTP Anonymous Access FTP Transfer Mode (ASCII vs Binary) FTP Resume (REST Command) SCP (Secure Copy Protocol) FTP Chroot Jail WebDAV (Web Distributed Authoring and Versioning) rsync FTP MLSD (Machine-Readable Listing) FTP NAT Traversal Transfer Integrity FTP over TLS (RFC 4217) File Locking Bandwidth Throttling TLS Versions

Frequently Asked Questions

What is FTP 451 Local Error?

Requested action aborted: local error in processing. The server encountered an unexpected error while trying to complete the command.

When do you see FTP 451 Local Error?

When the server has an internal issue like a disk I/O error, memory shortage, or filesystem problem during command processing.

How to fix FTP 451 Local Error?

Retry the command. If the error persists, contact the server administrator to check disk health, available memory, and server logs.