RFC 2505:Anti-Spam Recommendations for SMTP MTAs
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Denial of Service Attack


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... might result in problems for the DNS server itself to cope with the load. This itself can result in a denial of service attack against the DNS server just by sending email ...
... DNS, forged DNS responses can be used to mount denial of service attacks. For example, if a site is known to implement a FQDN validity ...


... It should be noted that by logging more events, especially denied email, one opens the possibility for denial of service attacks, for example by filling logs by having a very large amount of "RCPT To:" commands. An implementation that implements increased logging ...
... MTA will re-run its mail queue, which may be quite costly and open for Denial of Service attacks. Therefore, the MTA SHOULD control who is is allowed to issue the ETRN ...


... methods described in this document will, because of that, increase the risk of a denial of service attack against the support system by sending spam to a site. Logging facilities must for example be able to handle ...



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