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3376046 - SAPFTP - active mode connection hangs then fails with Accept on data channel failed : NIETIMEOUT timeout 720000 ms

Symptom

***** Consulting KBA, not a proposal from SAP development nor SAP product support *****

  • Standard TCP/IP RFC destinations SAPFTP/SAPFTPA are called via ABAP to initiate an FTP transfer.
  • Active mode FTP connection used.
  • Error Accept on data channel failed : NIETIMEOUT timeout 720000 ms occurs.
  • Passive mode transfer functions properly.
  • tcpdump/wireshark packet trace shows PORT command attempting to reuse the same port within a short timeperiod (less than 60 seconds).
  • Operating system kernel parameter net.ipv4.tcp_tw_reuse is set to 0 or 2.
  • The file /proc/sys/net/ipv4/ip_local_reserved_ports contains high number of ports and port ranges.
  • Parameter reserved_port/enable is not set at all or set to true in the SAP Host Agent's profile.

dev_ftp contains similar error message

Thr 140736265546080] [289581] > PORT 1xx,xx,x,xx,35,43
Thr 140736265546080] Conversion method: rscpCConvertt(4103, 4110) = 0
Thr 140736265546080] [289581] FTP server : 200 Port command successful
Thr 140736265546080] [289581] > RETR xxxxxxxxxxxxxxxx_0.pdf
Thr 140736265546080] Conversion method: rscpCConvertt(4103, 4110) = 0
Thr 140736265546080] [289581] FTP server : 150 Opening data channel for file download from server of "/XI/xxxxxx/xxxxx/Q/xxxxxxx/Archive/PDF/xxxxxxxxxxxx.pdf
Thr 140736265546080] Thu Sep 7 15:50:05 2023
Thr 140736265546080] *** ERROR => [289581] Accept on data channel failed : NIETIMEOUT timeout 720000 ms [ftpnw.c 410]
Thr 140736265546080] Thu Sep 7 15:50:06 2023
Thr 140736265546080] [289581] FTP Stop

Wireshark packet trace


Read more...

Environment

  • SuSE Linux Enterprise Server 15 (x86_64 and ppcle)
  • SAP S/4HANA 2021

Product

SAP S/4HANA 2021

Keywords

reserved_port/enable, /proc/sys/net/ipv4/ip_local_reserved_ports, net.ipv4.tcp_tw_reuse, SAPFTP, active mode connection , KBA , BC-SRV-COM-FTP , File Transfer via FTP , Problem

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