ANSWERS GUARANTEE A+
✔✔What is CSMA/CD? - ✔✔Used by ethernet to prevent collisions
✔✔What is a token ring? - ✔✔A communication standard like ethernet but less chance
of collisions, uni-directional, half duplex.
✔✔What does FHRP stand for? - ✔✔First Hop Redundancy Protocol
✔✔What does FHRP do? - ✔✔Protects default gateways by allowing two or more router
to provide backup for that address. Meaning if the active router fails, the backup router
takes it's place.
✔✔How does the backup router detect if the active router is down? (FHRP) - ✔✔Both
Active and Backup routers send a HELLO broadcast message periodically, so if a
HELLO message is not received by the backup router then it assumes the active router
is dead.
✔✔What are the three FHRP Protocols? - ✔✔HSRP (Hot Standy Router Protocol),
VRRP ( Virtual Router Redundancy Protocol) and GLBP (Gateway load-balancing
protocol)
✔✔What is DES (Bit key size, block size) - ✔✔DES uses a 56 bit key with a 64 bit block
✔✔What is 3DES (Bit key size, block size) - ✔✔112/168 Bit key, 64 bit block and
applies the DES algorithm 3 times
✔✔What is AES (Block size, Key size) - ✔✔128 Bit Block and then a 128,192 or 256 bit
key.
✔✔What is a Block Cipher? - ✔✔A block cipher is a method of encrypting text (to
produce ciphertext) in which a cryptographic key and algorithm are applied to a block of
data (for example, 64 contiguous bits) at once as a group rather than to one bit at a
time.
✔✔What is a Stream Cipher - ✔✔An encryption method that encrypts a single bit at a
time. Popular when data comes in long streams (such as with older wireless networks
or cell phones).
✔✔What is RC4 (Key size) - ✔✔Stream Symmetric cipher, key size of 40-2048 bits.
✔✔State some Asymmetric algorithms? - ✔✔RSA (1024-4096), ECC, DSA and DH
,✔✔What is HMAC? - ✔✔HMAC is a keyed-hash message authentication code used to
provide a checksum for a message, sent along with the message to provide confidence
that the message has not been tampered.
✔✔What is PGP? - ✔✔Pretty Good Privacy: An encryption program that provides
cryptographic privacy and authentication for data communication (such as emails).
✔✔What two protocols does IPsec use? - ✔✔Authentication Header (AH) and
Encapsulating Security Payload (ESP)
✔✔What is AH? - ✔✔Authentication Header (AH) authenticates the source of an IP
packet and verifies the integrity of the content.
✔✔What is ESP? - ✔✔Encapsulating Security Payload (ESP) encrypts an entire packet
and authenticates the content.
✔✔What is Internet Key Exchange? - ✔✔IKE is a protocol used to secure and
authenticate communication channels between two parties.
✔✔What does IKE Phase 1 do? - ✔✔Establishes a secure authenticated
communication channel using the Diffie-Hellman key exchange algorithm and generates
a shared secret key which is used in further IKE communications.
✔✔What modes can Phase 1 operate in? - ✔✔Either Main Mode or Aggressive Mode.
With Main Mode protecting the identify of peers and the hash of the shared key by
encrypting them and aggressive mode does not.
✔✔What does IKE Phase 2 do? - ✔✔Operates in quick mode and uses ESP and AH.
✔✔What is IPsec vulnerable to? - ✔✔Passive decryption of data if a weak DH group is
used, RCE, active and passive enum using aggressive mode, exposure and cracking of
preshared key values, obtaining XAUTH creds once a PSK is known.
✔✔What port does whois use? - ✔✔43
✔✔What port does TACACS use? - ✔✔49
✔✔What port does DNS use? - ✔✔53
✔✔What port does DHCP use? - ✔✔UDP 67 and 68
✔✔What port does TFTP use? - ✔✔69
✔✔What port does finger use? - ✔✔79
, ✔✔What port does Kerberos use? - ✔✔88 and 464
✔✔What port does POP3 use? - ✔✔110
✔✔What port does rpc use? - ✔✔111
✔✔What port does ident use? - ✔✔113
✔✔What port does NNTP use? - ✔✔119
✔✔What port does NTP use? - ✔✔123
✔✔What port does NBT use? - ✔✔137
✔✔What port does IMAP4 use? - ✔✔143
✔✔What port does SNMP use? - ✔✔161 and 162 UDP
✔✔What port does BGP use? - ✔✔179
✔✔What port does LDAP use? - ✔✔389
✔✔What port does rexec, rlogin and rsh use? - ✔✔512, 513 and 514
✔✔What port does (FTP + TLS) FTPS use? - ✔✔989
✔✔What port does Internet Message Access Protocol (IMAPS) use? - ✔✔993
✔✔What port does OpenVPN use? - ✔✔1194
✔✔What port does MSSQL use? - ✔✔1433, 1434 and 2433
✔✔What port does Oracle use? - ✔✔1521, 1522, 1526, 1541 and 1830
✔✔What port does L2TP use? - ✔✔1702
✔✔What port does Radius Authentication and Accounting use? - ✔✔1812 and 1813
✔✔What port does NFS use? - ✔✔2049
✔✔What port does Squid Proxy use? - ✔✔3124