Term Test #2 - 20% - Answer Key 1. [Points: 2] What changes were made to the ICMP "Datagram Too Big" message to accommodate PMTU (Path Maximum Transmission Unit) discovery? [week05notes.txt] 2. [Points: 2] What was the purpose of the "Requirements for Internet Hosts" documents RFC-1123 and 1124? [week05notes.txt] 3. [Points: 2] Why was EHLO added to SMTP, if SMTP already had HELO? [RFC1869 "This memo defines a framework for extending the SMTP service by defining a means whereby a server SMTP can inform a client SMTP as to the service extensions it supports." SMTP HELO had no version or way of using extensions.] 4. [Points: 5] What are the five meanings of the first digit of an SMTP response? [RFC2821 section 4.2.1] 5. [Points: 2] How are SMTP responses continued onto multiple lines? [RFC2821 section 4.2.1 p.44] 6. [Points: 1] How many bits in a byte are usable in an SMTP mail message? [RFC2821 section 4.5.2] 7. [Points: 2] How does SMTP escape message text so all lines can be sent safely after a DATA command? [RFC2821 section 4.5.2] 8. [Points: 1] A standard SMTP client MUST wait for each server response before sending the next SMTP command; pipelining is not allowed by default: TRUE [RFC2821 section 4.3.1] 9. [Points: 1] When a client connects to an SMTP server, the server can wait up to five minutes before issuing its initial greeting message to the client: TRUE [RFC2821 section 4.5.3.2] 10. [Points: 1] The include file contains approximately the same number of temporary and permanent program exit codes: FALSE [it only has one temporary failure exit code] 11. [Points: 1] The Perl die() function returns a code from : FALSE [the behaviour of die() is documented in its section in "man perlfunc" - sysexits isn't used at all] 12. [Points: 2] Why was HTTP implemented using a text-based "Internet protocol" and not a binary RPC (remote procedure call)? [ http://www.w3.org/Protocols/DesignIssues.html ] 13. [Points: 2] How can the stateless nature of HTTP be mitigated for search systems? [ http://www.w3.org/Protocols/DesignIssues.html or mention using session tracking protocols ] 14. [Points: 4] Name and describe briefly two of three possible ways to implement implicit HTTP session tracking. [ http://www.brics.dk/~amoeller/WWW/javaweb/sessions.html ] 15. [Points: 2] What was the biggest efficiency change between HTTP version 1.0 and 1.1? [Persistent Connections] 16. [Points: 1] How many bits in a byte are usable in an HTTP data transfer? [week10notes.txt, RFC2616 section 7.2] 17. [Points: 2] Why does the IETF deprecate the use of separate port numbers for secure versions of Internet protocols? [week09notes.txt] 18. [Points: 2] Give an example of an HTTP "absolute URI" and circle the part(s) that are case-sensitive. [RFC2616 section 3.2.3 - http://www.idallen.com/(openformats.txt) ] 19. [Points: 1] What does HTTP define as the maximum length of a URI? [unlimited - RFC2616 section 3.2.1] 20. [Points: 2] How do HTTP clients and servers detect the end of a series of message header lines? [week09notes.txt, RFC2616 section 4.1] 21. [Points: 2] How can you fold a long line in HTTP 1.1? [week10notes.txt, RFC2616 section 2.2 p.16] 22. [Points: 1] List the names of the mandatory request header fields for HTTP 1.1 [week10notes.txt, RFC2616 sections 5.1.2, 9, 14.23] 23. [Points: 5] What are the five meanings of the first digit of an HTTP response? [week10notes.txt, RFC2616 section 6.1.1] 24. [Points: 2] What is a "safe" HTTP request method? [week10notes.txt, RFC2616 section 9.1.1] 25. [Points: 1] HTTP request methods and version strings are case- sensitive: TRUE [week09notes.txt, RFC2616 section 5.1.1, HTTP errata] 26. [Points: 1] SMTP command words are case-sensitive: FALSE [RFC2821 section 2.4]