[Tfug] blacklists

[Paul Scott]

The following is the information that is given for bouncing of messages 
sent from ultrasw.com subscribers to at least one listserve at 
Yahoogroups.com:

 >> Remote host said: 550 This system is configured to reject mail from
 >> 66.218.66.81 [66.218.66.81]
 >> (Host blacklisted - Found on Realtime Black List server
 >> 'relays.osirusoft.com')

I have a general idea what causes this but I am wondering what an ISP 
should do about something like this.  I ask because many of you 
understand this stuff and I'm not confident that ultrasw.com is going to 
take the best action.

TIA,

Paul Scott