IBM Support

Firewall resets FTP if the banner page is too large

Troubleshooting


Problem

The client connects to the server, but never receives a prompt to enter the logon ID or password. A client trace might show an EZA2590E message with the return code of 1121.745A7242, which is indicates that the connection has been reset. A server trace may show the interruption of a routine.

Cause

The server has a banner page that is larger than the MTU of the ftp server, or has been segmented before getting to the firewall. This causes the last byte to be something other than the carriage return/line feed (CRLF) characters x'0D0A'. Some firewalls have rulesets which require all messages to terminate with the CRLF characters, and will drop packets or reset connections whenever a non-conforming packet is received.

Resolving The Problem

Correct the problem by way of one of the following:

  • Modify the firewall's ruleset
  • Reduce the size of the FTP server's banner.

[{"Product":{"code":"SSSN3L","label":"z\/OS Communications Server"},"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Component":"All","Platform":[{"code":"PF035","label":"z\/OS"}],"Version":"1.6;1.7;1.8;1.9;1.10;1.11;1.12;1.13;2.1;2.2","Edition":"","Line of Business":{"code":"LOB35","label":"Mainframe SW"}}]

Document Information

Modified date:
15 June 2018

UID

swg21063937

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