俺也碰到了，重新启动服务器后FTP连接不上了

守株不待兔

正在连接到 www.bb.com, 端口 21 (#1)
解析主机为：192.168.0.105
已连接。正在等待响应。
220---------- Welcome to Pure-FTPd [privsep] ----------
220-You are user number 1 of 50 allowed.
220-Local time is now 19:56. Server port: 21.
220-This is a private system - No anonymous login
220-IPv6 connections are also welcome on this server.
220 You will be disconnected after 15 minutes of inactivity.
USER www_bb_com
331 User www_bb_com OK. Password required
PASS xxxxxx
230 OK. Current restricted y is /
SYST
215 UNIX Type: L8
REST 100
350 Restarting at 100. But we're in ASCII mode
REST 0
350 Restarting at 0
PWD
257 "/" is your current location
TYPE A
200 TYPE is now ASCII
PORT 192,168,0,101,5,97
200 PORT command successful
LIST
150 Connecting to port 5001
226-Options: -a -l
226 3 matches total
传输完成： 199 字节 / 0.015 秒 (13.27 KB/s)
CWD www.bb.com
250 OK. Current y is /www.bb.com
PWD
257 "/www.bb.com" is your current location
TYPE A
200 TYPE is now ASCII
PORT 192,168,0,101,5,102
200 PORT command successful
LIST
150 Connecting to port 5002
226-Options: -a -l
226 30 matches total
传输完成： 2,106 字节 / 0.016 秒 (131.63 KB/s)
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
CWD /
250 OK. Current y is /
PWD
257 "/" is your current location
TYPE A
200 TYPE is now ASCII
PORT 192,168,0,101,6,121
200 PORT command successful
LIST
150 Connecting to port 5003
226-Options: -a -l
226 3 matches total
传输完成： 199 字节 / 0.000 秒 (199.00 KB/s)
CWD www.bb.com
250 OK. Current y is /www.bb.com
PWD
257 "/www.bb.com" is your current location
CWD __ErrorFiles__
250 OK. Current y is /www.bb.com/__ErrorFiles__
PWD
257 "/www.bb.com/__ErrorFiles__" is your current location
TYPE A
200 TYPE is now ASCII
PORT 192,168,0,101,6,124
200 PORT command successful
LIST
150 Connecting to port 5004
226-Options: -a -l
226 12 matches total
传输完成： 852 字节 / 0.000 秒 (852.00 KB/s)
CDUP
250 OK. Current y is /www.bb.com
PWD
257 "/www.bb.com" is your current location
NOOP
200 Zzz...
TYPE I
200 TYPE is now 8-bit binary
PORT 192,168,0,101,6,126
200 PORT command successful
STOR tools.php
150 Connecting to port 5005
226-File successfully transferred
226 0.106 seconds (measured here), 1.47 Mbytes per second
传输完成： 163,246 字节 / 0.094 秒 (1736.66 KB/s)
CWD /www.bb.com/
250 OK. Current y is /www.bb.com
PWD
257 "/www.bb.com" is your current location
TYPE A
200 TYPE is now ASCII
PORT 192,168,0,101,6,128
200 PORT command successful
LIST
150 Connecting to port 5006
226-Options: -a -l
226 31 matches total
传输完成： 2,177 字节 / 0.016 秒 (136.06 KB/s)
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
CWD config
250 OK. Current y is /www.bb.com/config
PWD
257 "/www.bb.com/config" is your current location
TYPE A
200 TYPE is now ASCII
PORT 192,168,0,101,7,22
200 PORT command successful
LIST
150 Connecting to port 5007
226-Options: -a -l
226 6 matches total
传输完成： 461 字节 / 0.000 秒 (461.00 KB/s)
TYPE I
200 TYPE is now 8-bit binary
PORT 192,168,0,101,7,24
200 PORT command successful
RETR config_global.php
150 Connecting to port 5008
226-File successfully transferred
226 0.002 seconds (measured here), 1.79 Mbytes per second
传输完成： 3,956 字节 / 0.016 秒 (247.25 KB/s)
TYPE I
200 TYPE is now 8-bit binary
PORT 192,168,0,101,7,28
200 PORT command successful
STOR config_global.php
150 Connecting to port 5009
226-File successfully transferred
226 0.002 seconds (measured here), 1.77 Mbytes per second
传输完成： 3,958 字节 / 0.015 秒 (263.87 KB/s)
TYPE A
200 TYPE is now ASCII
PORT 192,168,0,101,7,30
200 PORT command successful
LIST
150 Connecting to port 5010
226-Options: -a -l
226 6 matches total
传输完成： 461 字节 / 0.000 秒 (461.00 KB/s)
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
200 Zzz...
NOOP
421 Timeout (no operation for 1800 seconds)
错误：连接被中止
正在连接到 www.bb.com, 端口 21 (#1)
解析主机为：192.168.0.105
已连接。正在等待响应。
220---------- Welcome to Pure-FTPd [privsep] ----------
220-You are user number 1 of 50 allowed.
220-Local time is now 21:03. Server port: 21.
220-This is a private system - No anonymous login
220-IPv6 connections are also welcome on this server.
220 You will be disconnected after 15 minutes of inactivity.
USER www_bb_com
331 User www_bb_com OK. Password required
PASS xxxxxx
530 Login authentication failed
QUIT
连接尝试失败。
正在连接到 www.bb.com, 端口 21 (#2)
解析主机为：192.168.0.105
已连接。正在等待响应。
220---------- Welcome to Pure-FTPd [privsep] ----------
220-You are user number 1 of 50 allowed.
220-Local time is now 21:03. Server port: 21.
220-This is a private system - No anonymous login
220-IPv6 connections are also welcome on this server.
220 You will be disconnected after 15 minutes of inactivity.
USER www_bb_com
331 User www_bb_com OK. Password required
PASS xxxxxx
530 Login authentication failed
QUIT
连接尝试失败。
正在连接到 www.bb.com, 端口 21 (#3)
解析主机为：192.168.0.105
已连接。正在等待响应。
220---------- Welcome to Pure-FTPd [privsep] ----------
220-You are user number 1 of 50 allowed.
220-Local time is now 21:03. Server port: 21.
220-This is a private system - No anonymous login
220-IPv6 connections are also welcome on this server.
220 You will be disconnected after 15 minutes of inactivity.
USER www_bb_com
331 User www_bb_com OK. Password required
PASS xxxxxx
530 Login authentication failed
QUIT
连接尝试失败。
正在连接到 www.bb.com, 端口 21 (#4)
解析主机为：192.168.0.105
已连接。正在等待响应。
220---------- Welcome to Pure-FTPd [privsep] ----------
220-You are user number 1 of 50 allowed.
220-Local time is now 21:03. Server port: 21.
220-This is a private system - No anonymous login
220-IPv6 connections are also welcome on this server.
220 You will be disconnected after 15 minutes of inactivity.
USER www_bb_com
331 User www_bb_com OK. Password required
PASS xxxxxx
530 Login authentication failed
QUIT
连接尝试失败。
正在连接到 www.bb.com, 端口 21 (#5)
解析主机为：192.168.0.105
已连接。正在等待响应。
220---------- Welcome to Pure-FTPd [privsep] ----------
220-You are user number 1 of 50 allowed.
220-Local time is now 21:04. Server port: 21.
220-This is a private system - No anonymous login
220-IPv6 connections are also welcome on this server.
220 You will be disconnected after 15 minutes of inactivity.
USER www_bb_com
331 User www_bb_com OK. Password required
PASS xxxxxx
530 Login authentication failed
QUIT
连接尝试失败。
正在连接到 www.bb.com, 端口 21 (#6)
解析主机为：192.168.0.105
已连接。正在等待响应。
220---------- Welcome to Pure-FTPd [privsep] ----------
220-You are user number 1 of 50 allowed.
220-Local time is now 21:04. Server port: 21.
220-This is a private system - No anonymous login
220-IPv6 connections are also welcome on this server.
220 You will be disconnected after 15 minutes of inactivity.
USER www_bb_com
331 User www_bb_com OK. Password required
PASS xxxxxx
530 Login authentication failed
QUIT
连接尝试失败。
正在连接到 www.bb.com, 端口 21 (#7)
解析主机为：192.168.0.105
已连接。正在等待响应。
220---------- Welcome to Pure-FTPd [privsep] ----------
220-You are user number 1 of 50 allowed.
220-Local time is now 21:04. Server port: 21.
220-This is a private system - No anonymous login
220-IPv6 connections are also welcome on this server.
220 You will be disconnected after 15 minutes of inactivity.
USER www_bb_com
331 User www_bb_com OK. Password required
PASS xxxxxx

守株不待兔

CENTOS 6

pureftpd-restart 后就可以了