331
FTP
331 Username OK, Need Password
User name okay, need password. The server recognized the username and is waiting for the corresponding password to complete authentication.
이 코드를 보게 되는 경우
After sending the USER command with a valid username. The server is prompting for the PASS command.
해결 방법
Send the PASS command with the correct password. If you get 530 after PASS, the password is wrong — verify your credentials.
비교 대상
가이드
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
용어집
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