On 14 Jun 2011, at 05:24, Phil Pennock wrote: > On 2011-06-13 at 00:32 +0000, Michael Jimenez wrote: >> So I've been looking at my mail server mainlog for the past couple of days >> watching mail come in and out, I've noticed that this Microsoft address >> keeps failing to verify: > > You're using sender *callout* verification to systems not under your > administrative control. This is regarded by many as abusive, and will > get you placed on various blacklists.
Is that true? I've not experienced it, in several years. > The larger providers have rate-limits and other DoS filters; so when an > MSN address is spoofed and you keep hitting their mail-servers with > checks on mails they didn't send, you'll exceed ratelimits and get > fast-failed: they're rejecting you attempting to deliver to them, which > you're interpreting to mean that the address is invalid. That's not likely to happen. Exim's result caching means you're not going to be making frequent callouts regarding a single address. In theory, it could happen if spammers were attempting to deliver to you from many different addresses in the same domain, in rapid succession. However, you could -and should- mitigate against that by doing callouts late. > Sender callouts are best suited for use to systems under your own > control. -- Ian Eiloart Postmaster, University of Sussex +44 (0) 1273 87-3148 -- ## List details at https://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
