Q: "Why those major known business corporations got blacklisted by the Internet antispam forces?"
A: "E-mail admins of those major known business corporations have had their servers misconfigured, which allowed spamers to use those servers as free relays and abuse internet users community. After confirmed complain from internet users the IP address of those servers got blacklisted. It is those companies responsibility to have their systems healthy and contact internet authority to have them removed. The black list database is hold and maintained by INDEPENDENT Internet task force and it is REGARDLESS which product from which vendor is used in house."

Q: "Is it possible to check if a given IP is blacklisted?"
A: "Yes, it is! Just follow the links or"

Q: "What are the antispam recommendations for SMTP communication?"
A: "They are described in RFC2505"

Q: "What are the common DNS operational and configuration errors?"
A: "They are described in RFC1912"

Q: "What EXACTLY should major known business corporations do to be removed?"
A: "1. Go to AND to get familiar with the Domain Name System Real-time Black List
2. Make sure the blacklisted e-mail systems are configured properly.
3. Go get removed follow the instructions in your e-mail, which are similar to"

Q: "How much time it usually takes to be removed?"
A: "If systems are fixed it takes about an one hour to be removed."

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