rsync error when sending lot's of small files

[Johan Huysmans]

Hi All,

I have a problem when transferring files from a rsyncd.  This is my setup:
* server: runs rsyncd on port 873.
* firewall: forwarding for the 873 port from outside (using SNAT and DNAT).
* client: manually running rsync command using modules.

The problem occurs when lots of small identical files are being send.
Small is smaller than 400 bytes.

It also only occurs when the NATting happens, running it locally give no 
problems.

Also when i use the --sockopts=SO_SNDBUF=xxx argument on the rsyncd it 
won't occur, but i noticed that the transfer is generally slower. (I 
also have normal sizes files available)

I hope someone call help me or point me to the right direction.

Greetings Johan Huysmans