UNIX for Dummies Questions & Answers

Hi,

I'm puzzled at how this could be.

I'm trying to transfer some files from an Sun box to an AIX box via FTP. The file transfer goes fine until it reaches a file of about 150k then times out and fails.

The FTP Does not seem to be able to transfer files of more than 150k! However, I can transfer a compress file without any problems. The files I'm trying to grab are ASCII. I can transfer BINARY files easily no matter the size, but not ASCII.

Has anyone experienced this before?

The servers are on two separate networks and there are about 150,000 files in the directory I'm polling from.

A couple of things to try.

1) Lower the block size on the ftpd (in inetd.conf).

2) Lower the block size on the ftp client (e.g. -B 1).

3) Get you comms people to check that both machines have hard-set LAN speed (i.e. not auto-negotiation).

How do I lower the block size of the ftp client?

Code:

ftp -B 1B  hostname

This creates one 1024 byte block. Check your ftp man page you may not need the red B above.

Doesn't work on AIX.

Sorry to mislead you I can't find a way to change this in current Solaris or AIX. We really need Solaris to use 1k (not 8k) block size to talk to AIX. Others may know better.

The problem is often caused by ftp incorrectly negotiating (or defaulting) comms parameters to values only appplicable to that manufacturer on a fast LAN.

LAN speed auto-negotiation can cause this type of fault too.

It can be caused by routers incorrectly negotiating large packet sizes when not all routers on the route can deal with them.

The list is endless but usually reducing the ftp block size fixes the problem.