North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Port 25 filters - how many here deploy them bidirectionally?
On Sun, 9 Jan 2005 14:51:31 -0500 (EST), Sean Donelan <[email protected]> wrote: > On Sun, 9 Jan 2005, Suresh Ramasubramanian wrote: > > So, a quick poll .. how many ISPs here have noticed this behavior, and > > applied bidirectional filters? And if they've applied port 25 filters > > bidirectionally, have they noticed any problems with this setup? > > Have you looked at the following :-) > > http://www.outblaze.com/main.php?id=antispam&page=anti_infoadmin I wrote some part of that doc (though the part about filtering you quoted seems to have been written by a colleague) - you'll find docs all over the 'net, that have a lot more detail. Finding out how many ISPs are doing this is a rather different thing from finding out how many docs out there are recommending it. Especially as I'm seeing a marked uptick in this sort of behavior, from ISPs that I thought normally do filter port 25. As John points out earlier there were cases of specific people doing this, though now I think we're seeing trojans do it - a rather more dangerous development. --srs -- Suresh Ramasubramanian ([email protected])
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