1. An IP packet has arrived with the first 8 bits as 01000010. What is the version?.
A. 3.
B. 4.
C. 5.
D. 6.
Answer= 4
2. An IP packet has arrived with the first 8 bits as 01000010. What is the header length?.
A. 4.
B. 8.
C. 12.
D. 16.
Answer= 8
3. In an IP packet, the value of HLEN is 1000 in binary. How many bytes of options are being carried by this packet?.
A. 16.
B. 64.
C. 32.
D. 8.
Answer= 32
4. In an IP packet, the value of HLEN is 5_16 and the value of the total length field is 0028_16. How many bytes of data are being carried by this packet?.
A. 10.
B. 40.
C. 60.
D. 20.
Answer= 20
5. In an IP packet, the value of HLEN is 516 and the value of the total length field is 002816.What is the efficiency of this datagram?.
A. 80%.
B. 50%.
C. 66%.
D. 75%.
Answer= 50%
6. An IP packet has arrived with the first few hexadecimal digits as shown: 45000028000100000102 . . . How many hops can this packet travel before being dropped?.
A. 2.
B. 5.
C. 3.
D. 1.
Answer= 1
7. An IP packet has arrived with the first few hexadecimal digits as shown: 45000028000100000102 . . . The data belong to what upper layer protocol?.
A. IGMP.
B. UDP.
C. OSPF.
D. TCP.
Answer= IGMP
8. A packet has arrived in which the offset value is 100. What is the number of the first byte?.
A. 400.
B. 800.
C. 200.
D. 780.
Answer= 800
9. A packet has arrived in which the offset value is 100, the value of HLEN is 5 and the value of the total length field is 100. What is the number of the first byte?.
A. 800.
B. 880.
C. 400.
D. 780.
Answer= 800
10. A packet has arrived in which the offset value is 100, the value of HLEN is 5 and the value of the total length field is 100. What is the number of the last byte.
A. 880.
B. 879.
C. 881.
D. 801.
Answer= 879
11. Convert the following binary notation to dotted-decimal notation –10000000 00001011 00000011 00011111.
A. 128.11.5.32.
B. 128.11.3.31.
C. 127.11.3.32.
D. 127.12.5.31.
Answer= 128.11.3.31
12. Convert the following binary notation to hexadecimal notation –10000000 00001011 00000011 00011111.
A. 0x 80 0B 03 1E.
B. 0x 81 0B 04 1E.
C. 0x 80 0C 03 1F.
D. 0x 80 0B 03 1F.
Answer= 0x 80 0B 03 1F
13. Convert the following binary notation to dotted-decimal notation –10000001 00001011 00001011 11101111.
A. 129.11.11.239.
B. 128.11.12.231.
C. 127.11.13.244.
D. 129.12.1.231.
Answer= 129.11.11.239
14. Convert the following dotted-decimal notation to binary notation – 111.56.45.78.
A. 01101111 00111000 00101101 01001110.
B. 11101111 00111000 00101101 10001110.
C. 10000000 00001011 00000011 00011111.
D. 10000001 00001011 00001011 11101111.
Answer= 01101111 00111000 00101101 01001110
15. What is the error (if any) in the following representation – 111.56.045.78?.
A. There should be no leading zeros.
B. We cannot have more than 4 bytes in an IPv4 address.
C. Each byte should be less than or equal to 255.
D. No error.
Answer= There should be no leading zeros
16. What is the error (if any) in the following representation – 221.34.7.8.20?.
A. There should be no leading zeros.
B. Each byte should be less than or equal to 255.
C. We cannot have more than 4 bytes in an IPv4 address.
D. No error.
Answer= We cannot have more than 4 bytes in an IPv4 address
17. What is the error (if any) in the following representation – 75.45.301.14?.
A. There should be no leading zeros.
B. We cannot have more than 4 bytes in an IPv4 address.
C. Each byte should be less than or equal to 255.
D. No error.
Answer= Each byte should be less than or equal to 255
18. What is the error (if any) in the following representation – 11100010.23.14.67?.
A. There should be no leading zeros.
B. We cannot have more than 4 bytes in an IPv4 address.
C. Each byte should be less than or equal to 255.
D. None of the mentioned.
Answer= None of the mentioned
19. The following IPv4 addresses in hexadecimal notation is – 10000001 00001011 00001011 11101111
A. 0x810B0BEF.
B. 0x810D0AFF.
C. 0x810B0BFE.
D. 0x810C0CEF.
Answer= 0x810B0BEF
20. Find the number of addresses in a range if the first address is 146.102.29.0 and last address is 146.102.32.255..
A. 1028.
B. 1024.
C. 578.
D. 512.
Answer= 1024
21. The first address in a range of addresses is 14.11.45.96. If the number of addresses in the range is 32, what is the last address?.
A. 14.11.44.64.
B. 14.11.44.128.
C. 14.12.44.128.
D. 14.11.45.127.
Answer= 14.11.45.127
22. Each block in class A contains _____________ addresses..
A. 216.
B. 224.
C. 28.
D. 214.
Answer= 224
23. Each block in class B contains __________ addresses..
A. 28.
B. 224.
C. 214.
D. 216.
Answer= 216
24. Number of Blocks in class B are
A. 212.
B. 216.
C. 214.
D. 218.
Answer= 214
25. Number of Blocks in class C are
A. 212.
B. 216.
C. 214.
D. 218.
Answer= 214
26. Percent of addresses occupied by Class D?.
A. 50%.
B. 25%.
C. 6.25%.
D. 12.50%.
Answer= 6.25%
27. Which of the following does not have a Net ID and Host ID?.
A. Class A.
B. Class B.
C. Class C.
D. Class D.
Answer= Class D
28. Which Class is reserved for future use?.
A. A.
B. B.
C. D.
D. None of the Mentioned.
Answer= None of the Mentioned
29. Number of Blocks in class C are
A. 27.
B. 28.
C. 214.
D. 29.
Answer= 27
30. What is the size of the Host ID in Class C?.
A. 24 bits.
B. 16 bits.
C. 8 bits.
D. 14 bits.
Answer= 8 bits
31. Address of the block is
A. 214.
B. 216.
C. 28.
D. 224.
Answer= 216
32. First Address is
A. 180.8.0.0.
B. 180.7.64.0.
C. 180.8.1.256.
D. 180.12.0.0.
Answer= 180.8.0.0
33. Last Address is
A. 180.8.255.255..
B. 180.8.255.0..
C. 180.12.0.255..
D. 180.9.255.255..
Answer= 180.8.255.255.
34. A router receives a packet with the destination address 132.7.21.84. Find the network address of the packet..
A. 1.32.7.
B. 132.7.
C. 13.27.
D. 21.84.
Answer= 132.7
35. Classless Addressing overcomes the problem of
A. address completion.
B. address depletion.
C. address extraction.
D. all of the mentioned.
Answer= address depletion
36. Which of the following is true for classless addressing?.
A. The addresses are contiguous.
B. The number of addresses is a power of 2 (16 = 24), and the first address is divisible by 16.
C. The first address, when converted to a decimal number, is 3,440,387,360, which when divided by 16 results in 215,024,210.
D. All of the mentioned.
Answer= All of the mentioned
37. The value 'n' in classless addressing is referred to as
A. prefix length.
B. suffix length.
C. intermediate length.
D. none of the mentioned.
Answer= prefix length
38. Which of the following values can 'n' not take?.
A. 16.
B. 8.
C. 20.
D. 24.
Answer= 20
39. The slash notation in classless addressing is referred to as
A. NIFT.
B. PITF.
C. CIDR.
D. TRS.
Answer= CIDR
40. CIDR stands for
A. Class In Domain Range.
B. Classless Inter Domain Routing.
C. Classless In Domain Range.
D. None of the mentioned..
Answer= Classless Inter Domain Routing
41. A classless address is given as 167.199.170.82/27. Find the number of addresses..
A. 128.
B. 64.
C. 32.
D. 16.
Answer= 32
42. A classless address is given as 167.199.170.82/27. Find the first address..
A. 167.199.170.32.
B. 167.199.170.82.
C. 167.199.170.64.
D. 167.199.170.78.
Answer= 167.199.170.64
43. A classless address is given as 167.199.170.82/27. Find the last address..
A. 167.199.170.95.
B. 167.199.170.256.
C. 167.199.170.128.
D. 167.199.170.88.
Answer= 167.199.170.95
44. No. of address in the block= N= NOT(mask)+1..
A. TRUE.
B. FALSE.
C. Nothing can be said.
D. None of the mentioned.
Answer= TRUE
45. ICANN stands for Internet Corporation for Assigned Names and Addresses..
A. TRUE.
B. FALSE.
C. Nothing can be said.
D. None of the mentioned.
Answer= TRUE
46. An ISP has rested a block of 1000 addresses. How many blocks are granted to it?.
A. 512.
B. 1000.
C. 1024.
D. None of the mentioned.
Answer= 1024
47. An ISP has rested a block of 1000 addresses. What is its prefix length?.
A. 28.
B. 22.
C. 26.
D. 24.
Answer= 22
48. An ISP has rested a block of 1000 addresses. Can 18.14.12.0 be its first address?.
A. Yes.
B. No.
C. Can't Say.
D. Insufficient Data.
Answer= Yes
49. If the first address is First address = 18.14.12.0/22. What is the last address?.
A. 18.14.15.128/22.
B. 18.14.15.64/22.
C. 18.14.15.32/22.
D. 18.14.15.255/22.
Answer= 18.14.15.255/22
50. N_sub = n + log_2(N/N_sub) is used to find the suffix length..
A. TRUE.
B. FALSE.
C. Nothing can be said.
D. None of the mentioned.
Answer= FALSE
51. An organization is granted the block 130.34.12.64/26. Find the number of addresses for the whole network..
A. 128.
B. 32.
C. 256.
D. None of the mentioned.
Answer= None of the mentioned
52. An organization is granted the block 130.34.12.64/26. What is the last address of the network?.
A. 130.34.12.63/26.
B. 130.34.12.64/26.
C. 130.34.12.127/26.
D. 130.34.12.128/28.
Answer= 130.34.12.127/26
53. An organization is granted the block 130.34.12.64/26. The organization needs four subnetworks, each with an equal number of hosts. What is the number of addresses to each subnetwork?.
A. 4.
B. 16.
C. 8.
D. 32.
Answer= 16
54. In the above stion, what is the subnetwork mask for each network?.
A. 27.
B. 29.
C. 28.
D. 26.
Answer= 28
55. An organization is granted the block 130.34.12.64/26. The organization needs four subnetworks, each with an equal number of hosts. What is the first address for the 3rd subnetwork?.
A. 130.34.12.64/28.
B. 130.34.12.96/28.
C. 130.34.12.96/26.
D. 130.34.12.80/27.
Answer= 130.34.12.96/28
56. Number of addresses :.
A. 64.
B. 128.
C. 256.
D. 512.
Answer= 256
57. Last Address
A. 14.24.74.64/24.
B. 14.24.74.127/24.
C. 14.24.74.255/24.
D. 14.24.74.256/24.
Answer= 14.24.74.255/24
58. The subnet mask nsub1=
A. 23.
B. 25.
C. 26.
D. 27.
Answer= 25
59. First address of the second subblock
A. 14.24.74.192/26.
B. 14.24.74.128/26.
C. 14.24.74.127/28.
D. 14.24.74.67/27.
Answer= 14.24.74.128/26
60. Nsub3 =
A. 16.
B. 14.
C. 12.
D. 10.
Answer= 16
61. First Address of the third subblock
A. 14.24.74.128/28.
B. 14.24.74.127 /28.
C. 14.24.74.192/27.
D. 14.24.74.192/28.
Answer= 14.24.74.192/28
62. The subnet mask nsub3=
A. 28.
B. 27.
C. 26.
D. 24.
Answer= 28
63. Loopback address is given by
A. 0.0.0.0.
B. 127.x.x.x.
C. 255.255.255.255.
D. None of the mentioned.
Answer= 127.x.x.x
64. Broadcast address is given by
A. 0.0.0.0.
B. 127.x.x.x.
C. 255.255.255.255.
D. None of the mentioned.
Answer= 255.255.255.255
65. Network address is given by
A. 0.0.0.0.
B. 127.x.x.x.
C. 255.255.255.255.
D. None of the mentioned.
Answer= 0.0.0.0
66. In terms of Web Security Threats, "Impersonation of another user" is a Passive Attack..
A. TRUE.
B. FALSE.
C. Nothing can be said.
D. None of the mentioned.
Answer= FALSE
67. Which one of the following is not a higher –layer SSL protocol?.
A. Alert Protocol.
B. Handshake Protocol.
C. Alarm Protocol.
D. Change Cipher Spec Protocol.
Answer= Alarm Protocol
68. Which one of the following is not a session state parameter?.
A. Master Secret.
B. Cipher Spec.
C. Peer Certificate.
D. Server Write Key.
Answer= Server Write Key
69. In the SSL Protocol, each upper layer message if fragmented into a maximum of __________ bytes..
A. 216.
B. 232.
C. 214.
D. 212.
Answer= 214
70. The difference between HMAC algorithm and SSLv3 is that pad1 and pad2 are ________ in SSLv3 whereas ________ in HMAC..
A. NANDed, XORed.
B. Concatenated, XORed.
C. XORed, NANDed.
D. XORed, Concatenated.
Answer= Concatenated, XORed
71. The full form of SSL is.
A. Serial Session Layer.
B. Secure Socket Layer.
C. Session Secure Layer.
D. Series Socket Layer.
Answer= Secure Socket Layer
72. After the encryption stage in SSL, the maximum length of each fragment is.
A. 214+1028.
B. 214+2048.
C. 216+1028.
D. 216+2048.
Answer= 214+2048
73. Which protocol is used to convey SSL related alerts to the peer entity?.
A. Alert Protocol.
B. Handshake Protocol.
C. Upper-Layer Protocol.
D. Change Cipher Spec Protocol.
Answer= Alert Protocol
74. Which protocol consists of only 1 bit?.
A. Alert Protocol.
B. Handshake Protocol.
C. Upper-Layer Protocol.
D. Change Cipher Spec Protocol.
Answer= Change Cipher Spec Protocol
75. Which protocol is used for the purpose of copying the pending state into the current state?.
A. Alert Protocol.
B. Handshake Protocol.
C. Upper-Layer Protocol.
D. Change Cipher Spec Protocol.
Answer= Change Cipher Spec Protocol
76. Which of the following are possible sizes of MACs?i) 12 Bytesii) 16 Bytesiii) 20 Bytesiv) 24 Bytes.
A. i and iii.
B. ii only.
C. ii and iii.
D. ii iii and iv.
Answer= ii and iii
77. In the alert protocol the first byte takes the value 1 or 2 which corresponds to _________ and _________ respectively..
A. Select, Alarm.
B. Alert, Alarm.
C. Warning, Alarm.
D. Warning, Fatal.
Answer= Warning, Fatal
78. Number of phases in the handshaking protocol?.
A. 2.
B. 3.
C. 4.
D. 5.
Answer= 4
79. In the SSL record protocol operation pad_2 is
A. is the byte 0x36 repeated 40 times for MD5.
B. is the byte 0x5C repeated 48 times for MD5.
C. is the byte 0x5C repeated 48 times for SHA-1.
D. is the byte 0x36 repeated 48 times for MD5.
Answer= is the byte 0x5C repeated 48 times for MD5
80. In the SSL record protocol operation pad_1 is
A. is the byte 0x36 repeated 40 times for MD5.
B. is the byte 0x5C repeated 40 times for MD5.
C. is the byte 0x5C repeated 48 times for SHA-1.
D. is the byte 0x36 repeated 48 times for MD5.
Answer= is the byte 0x36 repeated 48 times for MD5
81. In the Handshake protocol action, which is the last step of the Phase 2 : Server Authentication and Key Exchange?.
A. server_done.
B. server_key_exchange.
C. certificate_rest.
D. crtificate_verify.
Answer= server_done
82. Which is the key exchange algorithm used in CipherSuite parameter?.
A. RSA.
B. Fixed Diffie-Hellman.
C. Ephemeral Diffie-Hellman.
D. Any of the mentioned.
Answer= Any of the mentioned
83. The certificate message is required for any agreed-on key exchange method except _______________.
A. Ephemeral Diffie-Hellman.
B. Anonymous Diffie-Hellman.
C. Fixed Diffie-Hellman.
D. RSA.
Answer= Anonymous Diffie-Hellman
84. In the Phase 2 of the Handshake Protocol Action, the step server_key_exchange is not needed for which of the following cipher systems?.
A. Fortezza.
B. Anonymous Diffie-Hellman.
C. Fixed Diffie-Hellman.
D. RSA.
Answer= Fixed Diffie-Hellman
85. The DSS signature uses which hash algorithm?.
A. MD5.
B. SHA-2.
C. SHA-1.
D. Does not use hash algorithm.
Answer= SHA-1
86. The RSA signature uses which hash algorithm?.
A. MD5.
B. SHA-1.
C. MD5 and SHA-1.
D. None of the mentioned..
Answer= MD5 and SHA-1
87. What is the size of the RSA signature hash after the MD5 and SHA-1 processing?.
A. 42 bytes.
B. 32 bytes.
C. 36 bytes.
D. 48 bytes.
Answer= 36 bytes
88. The certificate_rest massage includes two parameters, one of which is
A. certificate_extension.
B. certificate_creation.
C. certificate_exchange.
D. certificate_type.
Answer= certificate_type
89. The client_key_exchange message uses a pre master key of size
A. 48 bytes.
B. 56 bytes.
C. 64 bytes.
D. 32 bytes.
Answer= 48 bytes
90. In the handshake protocol which is the message type first sent between client and server ?.
A. server_hello.
B. client_hello.
C. hello_rest.
D. certificate_rest.
Answer= client_hello
91. In the SSLv3 the padding bits are ____________ with the secret key..
A. Padded.
B. XORed.
C. Concatenated.
D. ANDed.
Answer= Concatenated
92. Which of the following is not a valid input to the PRF in SSLv3?.
A. secret value.
B. identifying label.
C. initialization vector.
D. secret value.
Answer= initialization vector
93. Which of the following alert codes is not supported by SSLv3?.
A. record_overflow.
B. no_certificate.
C. internal_error.
D. decode_error.
Answer= no_certificate
94. We encounter the record_overflow error when the payload length exceeds
A. 214 + 1024.
B. 216 + 1024.
C. 214 + 2048.
D. 216 + 2048.
Answer= 214 + 2048
95. Which key exchange techni is not supported by SSLv3?.
A. Anonymous Diffie-Hellman.
B. Fixed Diffie-Hellman.
C. RSA.
D. Fortezza.
Answer= Fortezza
96. Calculation of the certificate_verify in TLS involves the use of a finished_label. The finished_label is the string
A. client finished for the client.
B. client finished for the client, server finished for the server.
C. server finished for the server.
D. client finished for the server, server finished for the client.
Answer= client finished for the client, server finished for the server
97. In TLS padding cann be upto a maximum of
A. 79 bytes.
B. 127 bytes.
C. 255 bytes.
D. none of the mentioned.
Answer= 255 bytes
98. URL stands for
A. Universal Remote Locator.
B. Universal Resource Language.
C. Uniform Resource Locator.
D. Uniform Resource Language.
Answer= Uniform Resource Locator
99. HTTPS stands for Hypertext Transfer Protocol over TLS..
A. TRUE.
B. FALSE.
C. Nothing can be said.
D. None of the mentioned.
Answer= TRUE
100. An HTTP connection uses port _________ whereas HTTPS uses port ____________ and invokes SSL..
A. 40; 80.
B. 60; 620.
C. 80; 443.
D. 620; 80.
Answer= 80; 443
101. Which of the following is not a secure shell protocol?.
A. Transport Layer Protocol.
B. Secure Layer Protocol.
C. Connection Protocol.
D. User Authentication Protocol.
Answer= Secure Layer Protocol
102. Which is the lowest level in the SSH protocol stack?.
A. SSH Transport Layer Protocol.
B. TCP.
C. IP.
D. SSH User Authentication Protocol.
Answer= IP
103. How many trust models does the RFC 4251 dictate?.
A. 2.
B. 3.
C. 4.
D. 5.
Answer= 2
104. Which is the correct order of the SSH Transport Layer Protocol Packet Exchanges?.
A. Algorithm Negotiation; End of key exchange; Service rest; Identification string exchange.
B. Identification string exchange; Algorithm Negotiation; End of key exchange; Service rest.
C. Identification string exchange; End of key exchange; Service rest; Algorithm Negotiation.
D. Algorithm Negotiation; Identification string exchange; End of key exchange; Service rest.
Answer= Identification string exchange; Algorithm Negotiation; End of key exchange; Service rest
105. The correct order of operations in the SSH Transport Layer Protocol Packet Formation is
A. Compression; Encryption; Padding and Addition of seq bits.
B. Compression; Padding and Addition of seq bits; Encryption.
C. Encryption; Padding and Addition of seq bits; Compression.
D. Padding and Addition of seq bits; Encryption; Compression.
Answer= Compression; Padding and Addition of seq bits; Encryption
106. Size of the sence number is
A. 32 bits.
B. 48 bits.
C. 56 bits.
D. 64 bits.
Answer= 32 bits
107. What is the recommended cryptographic algorithm for the Secure Shell Transport Layer?.
A. twofish 128.
B. aes 192.
C. aes 128.
D. blowfish.
Answer= aes 128
108. What is the recommended modes of operation for encryption and decryption in the Secure Shell Transport Layer?.
A. ECB.
B. OFB.
C. CBC.
D. CFB.
Answer= CBC
109. What is the recommended MAC algorithm for the SSH Transport Layer?.
A. HMAC – MD5.
B. HMAC – MD5 – 96.
C. HMAC SHA1 – 96.
D. HMAC SHA1.
Answer= HMAC SHA1 – 96
110. The session Identifier remains constant throughout the SSH connection..
A. TRUE.
B. FALSE.
C. Nothing can be said.
D. None of the mentioned.
Answer= TRUE
111. Which port forwarding techni intercepts application-level traffic and redirects it from an insecure TCP connections to secure SSH tunnels?.
A. Remote Forwarding.
B. Local Forwarding.
C. Stable Forwarding.
D. None of the mentioned.
Answer= Local Forwarding
112. The protocol 'POP' stands for
A. Personal Office Protocol.
B. Post Office Protocol.
C. Privacy Overall Protocol.
D. Privacy Over Protocol.
Answer= Post Office Protocol
113. In which port forwarding techni does the client act on the server's behalf?.
A. Remote Forwarding.
B. Local Forwarding.
C. Stable Forwarding.
D. None of the mentioned.
Answer= Remote Forwarding
114. In the User Authentication Protocol, when the client rests for authentication, then the first byte ( in this format) has decimal value
A. 80.
B. 60.
C. 50.
D. 61.
Answer= 50
115. SSH_MSG_USERAUTH_FALIURE is represented by byte
A. 50.
B. 51.
C. 52.
D. None of the mentioned.
Answer= 51
116. SSH_MSG_USERAUTH_SUCCESS is represented by the byte
A. 50.
B. 51.
C. 60.
D. None of the mentioned.
Answer= None of the mentioned
117. Which of the following are valid authentication methods?.
A. Public Key Based.
B. Password Based.
C. Host Based.
D. All of the mentioned.
Answer= All of the mentioned
118. The SSH Connection Protocol runs on top of the SSH Transport Layer Protocol and assumes that a secure authentication connection is in use..
A. TRUE.
B. FALSE.
C. Nothing can be said.
D. None of the mentioned.
Answer= TRUE
119. The secure authentication connection is referred to as
A. chisel.
B. tunnel.
C. zeroing.
D. handshaking.
Answer= tunnel
120. The Secure Shell Connection Protocol Message exchange has the fist phase as "Opening a Channel" and it sends a message with parameters-SSH_MSG_CHANNEL_OPENchannel typesender channelinnitial window sizemaximum packet sizeWhat is the data type sender channel/innitial window size/ channel type?.
A. uint16.
B. uint32.
C. int16.
D. int32.
Answer= uint32
121. In the "Opening a channel" phase what is the function of the "innitial window size" parameter?.
A. It specifies the number of bytes in the IV.
B. It specifies the maximum size of an individual packet.
C. It specifies how many bytes of channel data can be sent.
D. None of the mentioned.
Answer= It specifies how many bytes of channel data can be sent
122. In the "Opening a channel" phase what is the function of the "maximum packet size" parameter?.
A. It specifies the number of bytes in the IV.
B. It specifies the maximum size of an individual packet.
C. It specifies how many bytes of channel data can be sent.
D. None of the mentioned.
Answer= It specifies the maximum size of an individual packet
123. Which is not a channel recognized by the SSH connection protocol?.
A. session.
B. backward-tcpip.
C. direct-tcpip.
D. x11.
Answer= backward-tcpip
124. Which channel ensures local port forwarding?.
A. session.
B. x11.
C. forward-tcpip.
D. direct-tcpip.
Answer= direct-tcpip
125. On which port will the server generally listen to for SMTP?.
A. port 35.
B. port 63.
C. port 25.
D. port 65.
Answer= port 25