* Bernhard Schmidt <be...@birkenwald.de>: > Hi, > > among our userbase are a couple of thousand people that forward their > mail to other domains (mostly freemails). This has the obvious and > well-known downside that any spam going to this user looks like it > originated in our network, which might lead to some reputation problems. > And of course the nasty bounce/double-bounce issues...
Yes, it happens. > I wonder if there is any checklist how to deal with this situation best? > Something along the lines of > > - put forwards on a dedicated server That could help, since it's only THAT server that will get blacklisted. > - if you see too many fatal errors for a destination address, disable > forwarding Yes, this prevents the likes of t-online.de from blacklisting (your forwarding server) > - try to block as much spam as possible before forwarding (in our case > that would mean RBL and pre-queue filters, as we are not allowed to drop > mail we successfully received) I think you already have some sort of spam filtering in place? > Any other recommendations? Is SRS/PRVS helpful here? No, since the forwarding server will be blacklisted anyway (since it's the source). SRS can help nevertheless, since forwarding breaks SPF. As a benefit it allows you to notice bounces and react accordingly. -- Ralf Hildebrandt Geschäftsbereich IT | Abteilung Netzwerk Charité - Universitätsmedizin Berlin Campus Benjamin Franklin Hindenburgdamm 30 | D-12203 Berlin Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962 ralf.hildebra...@charite.de | http://www.charite.de
