I've been getting acknowledgements of reports from SBC lately so perhaps they are actually doing somthing for a change.
On the other hand, Kornet appear to have a new tactic:
QUOTE
leepy@kt.co.kr
SMTP error from remote mailer after MAIL FROM:<spamxreport@x.isp.com> SIZE=6340:
host smtp.kt.co.kr [147.6.45.66]: 503 Only one transaction
Only one transaction hmmmm ... per reporting address? per domain? per session? Not the latter I think, as it was not delivering multiple e-mails in one batch. Most strange.