[exim] Interesting log entry

Hello,

I noticed this log entry, which I have not seen before:

2007-08-23 11:17:49 SMTP protocol synchronization error (next input sent
too soon: pipelining was not advertised): rejected "Subject:¡erelay
ok¡f66.252.xxx.xxx" H=219-84-61-136-adsl-tpe.dynamic.so-net.net.tw
[219.84.61.136] next input="MIME-Version: 1.0\r\nContent-Type:
text/html;charset="big5"\r\nContent-Transfer-Encoding:7bit\r\n\263o\253\312\253H
relay from : 66.252.xxx.xxx\r\n.\r\n"

The 66.252 IP address is the IP address of our email server. This seems
to me like some attempt to exploit some vulnerability (looking at the
subject). But I don't expect exim to have problems with it.

Anyone know what it means and has seen something similar before? I am
just curious, not really concerned.

Thanks,
Jeroen