a /24 senders ip dnsbl
ivmSIP/24 is one of three invaluement DNSBLs. Please first read the discussion of goals and features shared by all 3 lists detailed on the invaluement Anti-Spam DNSBL page.
ivmSIP/24 is the invaluement /24 Senders IP DNSBL. Aka an RBL, this list includes those whole /24 blocks of IPs which only send spam. We recognize that the concept of /24 blacklists is not some amazing new idea we thought up. However, ivmSIP24 has two interesting distinctions:
- Unlike most other /24 DNSBLs, ivmSIP/24 is attempting to have the same extremely low false positive level as ivmSIP. In contrast, other /24 DNSBLs will admit that they are aggressive to a point where blocking legitimate e-mail is almost a given if used for outright blocking instead of scoring.
- Because all three invaluement DNSBLs are especially good at catching snowshoe spam, ivmSIP/24 is particularly useful for preemptively catching these same snowshoe spammers before a given IP is used to send spam the very first time. As a result, /24 blocks freshly allocated to snowshoe spammers will most likely get listed by ivmSIP/24 before getting listed by all other respected /24 DNSBLs.
A typical scenario is that a snowshoe spammer will acquire a /24 block, with the intention of spamming ever so slowly... one IP at a time... from that block. That tactic helps them to stay off the radar of just about every DNSBL. (Except they are caught by ivmSIP!) Eventually, our automated system detects their dastardly plans and their whole /24 block gets listed by ivmSIP/24 while they are merely a few IPs into burning up that block. Next, further attempts to send unsolicited messages from the rest of those virgin 200+ IPs in that block are preemptively blocked by ivmSIP/24, without having to wait on the first use of any of these IPs.
The difficulty with /24 blacklists is NOT mistakenly punishing innocent senders who happen to have IP allocation separate from the spammers, but which shares the same /24 block. And that is precisely why ivmSIP/24 is so new. For this very reason, we were reluctant to get into this /24 business. Until one day, several light bulbs went off and we developed several algorithms which enable the generation of an invaluement /24 blacklist which does not list innocent senders using address space adjacent to spammers. (At least, that is the goal. And reports from our subscribers, as well as our own internal testing, confirm overwhelming success!)
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a /24 senders ip dnsbl