Please eliminate SAV when requesting IP removal from our lists. A removal request generates at least two replies. Since the recipient IP is usually listed in the TQMcube DNSBL, the SAV probe will be rejected. We will not be able to communicate with you. Moreover, an SAV probe from a listed server is usually indistinguishable from backscatter. This could create additional listings.

Some sites may blacklist you when you are probing them too often or when you are probing them too often for a non-existent address. This is one reason why you should use sender address verification sparingly, if at all. You are consuming the resources of other servers.

SAV does not scale well. Assuming that nobody has too much available bandwidth or cycles, you are consuming your own resources in processing and caching the probes.

By default, some MTAs are mis-configured, sending the probes from a null sender. Many servers reject email from “<>” as a means of eliminating backscatter. Therefore, SAV may result in the rejection of valid email.