proftpd는 421 시간 초과 오류 메시지와 함께 세션을 종료합니다.

질문

Proftpd 1.3.6(1.3.1에서 업데이트되었으며 동일한 문제가 있음)의 연결은 다음 메시지와 함께 데이터를 전송하는 동안 종료됩니다.

421 전송 시간 제한 없음(3600초): 제어 연결을 닫습니다.

로그인 후 오류가 발생하는 데 걸리는 시간은 5초에서 몇 분까지 다양합니다. 로그(아래 발췌)를 확인했지만 이 동작에 대한 명확한 이유를 찾을 수 없었습니다. 이 오류는 한 명의 사용자만 연결되어 있고 동일한 사용자의 동시 세션이 열리는 경우 발생할 수 있습니다.

Wireshark에서는 "421: No Transmit Timeout"이 서버에서 클라이언트로 전송된 응답임을 표시합니다.

Proftpd는 ESXi 4.1의 상당히 오래된 가상화된 openSuse 시스템에서 실행됩니다. FTP 전송에는 이 계정만 ftpusr사용됩니다.

도움을 주셔서 미리 감사드립니다.

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로그 발췌

FTP 클라이언트 로그:

{snip}
150 Opening ASCII mode data connection for xyz_XML_Interface-Rawdata_20171124_16
1300_43864.tmp (597 bytes)
226 Transfer complete
ftp: 611 bytes received in 0.00Seconds 611000.00Kbytes/sec.
200 PORT command successful
150 Opening ASCII mode data connection for xyz_XML_Interface-Rawdata_20171209_06
5800_63895.tmp (443 bytes)
226 Transfer complete
ftp: 456 bytes received in 0.00Seconds 456.00Kbytes/sec.
200 PORT command successful
150 Opening ASCII mode data connection for xyz_XML_Interface-Rawdata_20171230_09
2000_93119.tmp (277 bytes)
226 Transfer complete
ftp: 288 bytes received in 0.00Seconds 288000.00Kbytes/sec.
421 No transfer timeout (3600 seconds): closing control connection
Connection closed by remote host.
ftp> mget *
Not connected.

Proftpd 디버그 출력:

다음 명령으로 proftpd를 시작할 때 화면 출력에서 ​​다음 로그를 가져옵니다 proftpd -d 5 -c /etc/proftpd.conf -n.

{snip}
2018-02-07 16:25:11,407 Oracle2db proftpd[15663] 10.15.87.17 (10.1.70.112[10.1.70.112]): dispatching PRE_CMD command 'PORT 10,1,70,112,229,162' to mod_core
2018-02-07 16:25:11,407 Oracle2db proftpd[15663] 10.15.87.17 (10.1.70.112[10.1.70.112]): dispatching PRE_CMD command 'PORT 10,1,70,112,229,162' to mod_core
2018-02-07 16:25:11,407 Oracle2db proftpd[15663] 10.15.87.17 (10.1.70.112[10.1.70.112]): dispatching CMD command 'PORT 10,1,70,112,229,162' to mod_core
2018-02-07 16:25:11,407 Oracle2db proftpd[15663] 10.15.87.17 (10.1.70.112[10.1.70.112]): dispatching LOG_CMD command 'PORT 10,1,70,112,229,162' to mod_log
2018-02-07 16:25:11,454 Oracle2db proftpd[15663] 10.15.87.17 (10.1.70.112[10.1.70.112]): dispatching PRE_CMD command 'RETR xyz_XML_Interface-Rawdata_20171129_064100_50277.tmp' to mod_core
2018-02-07 16:25:11,454 Oracle2db proftpd[15663] 10.15.87.17 (10.1.70.112[10.1.70.112]): dispatching PRE_CMD command 'RETR xyz_XML_Interface-Rawdata_20171129_064100_50277.tmp' to mod_core
2018-02-07 16:25:11,454 Oracle2db proftpd[15663] 10.15.87.17 (10.1.70.112[10.1.70.112]): dispatching PRE_CMD command 'RETR xyz_XML_Interface-Rawdata_20171129_064100_50277.tmp' to mod_auth
2018-02-07 16:25:11,454 Oracle2db proftpd[15663] 10.15.87.17 (10.1.70.112[10.1.70.112]): dispatching PRE_CMD command 'RETR xyz_XML_Interface-Rawdata_20171129_064100_50277.tmp' to mod_xfer
2018-02-07 16:25:11,454 Oracle2db proftpd[15663] 10.15.87.17 (10.1.70.112[10.1.70.112]): dispatching CMD command 'RETR xyz_XML_Interface-Rawdata_20171129_064100_50277.tmp' to mod_xfer
2018-02-07 16:25:11,505 Oracle2db proftpd[15663] 10.15.87.17 (10.1.70.112[10.1.70.112]): active data connection opened - local  : 10.15.87.17:20
2018-02-07 16:25:11,505 Oracle2db proftpd[15663] 10.15.87.17 (10.1.70.112[10.1.70.112]): active data connection opened - remote : 10.1.70.112:58786
2018-02-07 17:38:29,580 Oracle2db proftpd[15663] 10.15.87.17 (10.1.70.112[10.1.70.112]): Data transfer stall timeout: 3600 seconds
2018-02-07 16:25:11,566 Oracle2db proftpd[15663] 10.15.87.17 (10.1.70.112[10.1.70.112]): notice: user ftpusr: aborting transfer: Data connection closed

와이어샤크 스크린샷:

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구성

proftpd.conf:

# This is a basic ProFTPD configuration file (rename it to
# 'proftpd.conf' for actual use.  It establishes a single server
# and a single anonymous login.  It assumes that you have a user/group
# "nobody" and "ftp" for normal operation and anon.

ServerName                      "3.0 Linux-FTP"
ServerType standalone
DefaultServer                   on
RequireValidShell off
ExtendedLog /var/log/ftp.log
UseReverseDNS off
IdentLookups off
TimeoutLogin 120
TimeoutIdle 3600
TimeoutNoTransfer 3600
TimeoutStalled 3600
MaxClientsPerHost 2 "Two clients by hostname max"
MaxClientsPerUser 5 "Only one connection per user allowed"
MaxClients 4 "Too many users, please try again later"
MaxHostsPerUser 5 "Only one host per user allowed"
MaxLoginAttempts 2 "You've reached the max. login attempts"
UseSendfile off

# Port 21 is the standard FTP port.
Port                            21

# Umask 022 is a good standard umask to prevent new dirs and files
# from being group and world writable.
Umask                           022

# To prevent DoS attacks, set the maximum number of child processes
# to 30.  If you need to allow more than 30 concurrent connections
# at once, simply increase this value.  Note that this ONLY works
# in standalone mode, in inetd mode you should use an inetd server
# that allows you to limit maximum number of processes per service
# (such as xinetd).
MaxInstances                    30

# Set the user and group under which the server will run.
User                            ftpusr
Group                           ftpusers

# To cause every FTP user to be "jailed" (chrooted) into their home
# directory, uncomment this line.
DefaultRoot /home/ftpusr/xml-export
# DefaultRoot ~

# Normally, we want files to be overwriteable.
AllowOverwrite          on

<Directory /home/ftpusr/xml-export>
Umask 022 022
</Directory>