Resolving SecureCRT Errors with lrzsz in BSD

This article describes how to avoid transfer failures when running lrzsz on BSD.

Problem

When performing a Zmodem file upload using rz or lrz, SecureCRT aborts the transfer or hangs. This occurs when running lrzsz on FreeBSD or OpenBSD. The upload may complete for some small files, but not for others. The transfer may or may not start. When it fails in the middle, the CRC/checksum error count increases rapidly and the transfer rate slows down rapidly. The transfer may hang or pause indefinitely. SecureCRT may show an error message saying, "Zmodem transfer cancelled by remote side".

Cause

This problem may be caused by improper handling of escape sequences embedded in the files being uploaded.

Resolution

Use the -e or --escape option on lrz, which escapes control characters (Z). For example, type, lrz -e. Some Zmodem clients expect escaping, while others do not.

Notes

Note, some installations of lrzsz do not have the "sz" or "rz" commands, only "lsz" and "lrz". You can edit your .login file and add lines like "alias sz lsz" and "alias rz lrz -e". This way, when you type "sz" or "rz", it will automatically execute the right program with the right options.

lrzsz is part of the FreeBSD ports collection. It contains a set of shell commands for sending and receiving files via the X/Y/ZMODEM protocols. Your SSH or Telnet client must support them for transfers to work.

Applies To

Vandyke Software SecureCRT, lrzsz, lrzsz-0.12.20_1, FreeBSD, OpenBSD, BSD, ZModem, XModem, Verio VPS, Windows, SSH, telnet

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