2) SMTP (Simple Mail Transfer Protocol) is the standard prot…
2) SMTP (Simple Mail Transfer Protocol) is the standard protocol for transferring mail between hosts over TCP. A TCP connection is set up between a user agent and a server program. The server listens on TCP port 25 for incoming connection requests. The user end of the connection is on a TCP port number above 1023. Suppose you wish to build a packet filter rule set allowing inbound and outbound SMTP traffic. You generate the following rule set: ule Direction Src Addr Dest Addr Protocol Dest Port Action A In external internal TCP 25 permit B Out internal external TCP >1023 permit C Out internal external TCP 25 permit D In external internal TCP >1023 permit E Either any any any any deny a) Describe the effect of each rule.
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