OT - Help with resulting error message

[Steve Campbell]

John Wilcock wrote:
> Le 03/06/2009 16:25, Steve Campbell a écrit :
>> One of our users is trying to email users at a particular domain and is
>> receiving the following error message back from them:
>>
>> (reason: 550 5.7.1 rejected content, black listed twitter.com by
>> multi.surbl.org #762 #895 (l51Ehj043192426600))
>>
>> I asked if he was posting through twitter, and he said he was not. I
>> checked SURBL and our IPs are not listed. So I'm confused(as always) by
>> what this is telling me. He does have a reference to his twitter stuff
>> in his signature. Do any of the SURBL lists really block content?
>>
>> A good explanation would be helpful. Thanks much
>
> As I understand the discussions on the SURBL list, the gist of the 
> problem is that Chinese authorities have decided to block access to 
> Twitter in the run-up to the 20th anniversary of the Tienanmen square 
> protests, and SURBL have some DNS mirrors located behind the Great 
> Firewall, resulting in incorrect DNS responses from the affected servers.
>
> John.
>

Part of the original post question:

Does multi.surbl.org block on content, for instance, the reference to 
twitter.com in his signature. I thought they only listed offending 
sender's IP, not someone who referenced an offending senders domain name 
in an email.

steve