Network+ 8 Flashcards
A dedicated leased line is typically a point-to-point connection interconnecting two sites. All the bandwidth on that dedicated leased line is available to those sites. This means that, unlike a packet-switched connection, the bandwidth of a dedicated leased line connection does not need to be shared among multiple service provider customers. A single 64Kbps channel is called a Digital Signal 0 (DS0). When one of these circuits comes into your location, it terminates on a device called a channel service unit/data service unit (CSU/DSU). Also, be aware that a common Layer 2 protocol used on dedicated leased lines is Point-to-Point Protocol (PPP).
dedicated leased line
T1 circuit is 24 DSO channels at 1.544Mbps originally used in telephony networks.
Super Frame (SF): Combines 12 standard 193-bit frames into a super frame.
Extended Super Frame (ESF): Combines 24 standard 193-bit frames into an extended super frame. T1 circuits are popular in North America and Japan.
E1 has a bandwidth capacity of 2.048Mbps with 30 DSO channels, E1 circuits are popular outside of North America and Japan.
T3 circuit has a bandwidth capacity of 44.7Mbps with 672 DSO channels / E3 circuit is 34.4Mbps with 30 DSO channels.
T1 Circuit Etc …
arp -a/-g = displays current entries in PC’s arp table
arp -v = includes any invalid and loopback interface entries in ARP table
arp inet_addr : specifies IP address
arp -N if_addr : shows ARP entries learned for a specified network
arp -d : ARP entry can be deleted (with inet_addr parameter)
arp -s : statically adds host entry in ARP table (used with inet_addr/eth_addr)
arp eth_addr : is 48-bit MAC address
arp if_addr : This option can be used for statically adding or deleting an ARP entry to or from a specified interface.
ipconfig : /release and /release6; /renew and /renew6
nbtstat : displays NetBIOS information for IP-based networks.
Windows Commands
nbtstat -a remote_name : see NetBIOS table of remote PC with a NetBIOS name
nbtstat -A ip_address : see NetBIOS table of remote PC with an IP address
nbtstat -c : displays contents of PC’s NetBIOS name cache along with IP addresses corresponding to those NetBIOS names.
nbtstat -n : displays NetBIOS names that have been registered by an application
nbtstat -r : shows statistical NetBIOS info
nbtstat -R : This option purges a PC’s NetBIOS cache and reloads entries from a PC’s LMHOSTS file that have #PRE following the entry.
nbtstat - S : provides a listing of the NetBIOS session table, along with the IP addresses of the listed NetBIOS names.
netstat : display various information about IP-based connections on a PC.
netstat -a : displays all of a PC’s active IP-based sessions, along with the TCP and UDP ports of each session.
netstat -b : shows you the names of the program that opened up a session.
netstat -e : shows statistical information for an interface’s IP-based traffic, such as the number of bytes sent and received.
netstat -f : displays fully qualified domain names (FQDN) of destination addresses appearing in a listing of active sessions.
Windows Commands 2
netstat -p proto : displays connections for a specific protocol, which might be icmp, icmpv6, ip, ipv6, tcp, tcpv6, udp, or udpv6.
netstat -r : displays a PC’s IP routing table.
netstat -s : displays statistical information for the following protocols: icmpv4, icmpv6, ipv4, ipv6, tcpv4, tcpv6, udpv4, and udpv6.
nslookup command to resolve an FQDN to an IP address.
ping -t : This option repeatedly sends pings (ICMP echo messages) until you stop it by pressing Ctrl+C.
ping -n count : specifics number of pings to send
ping -f : sets the “don’t fragment” bit in a packet’s header. If the packet tries to cross a router that attempts to fragment the packet, the packet is dropped, and an ICMP error message is returned.
ping -i TTL : sets the TTL value in a packet’s header. The TTL is decremented for each router hop. A packet is discarded when its TTL value reaches 0.
ping -S srcaddr : If the PC from which you are issuing the ping command has more than one IP address, this option allows you to specify the source IP address from which the ICMP echo messages should be sent.
ping target_name : specifies the name or the IP address of the device to which you are sending ICMP echo messages.
route command can display a PC’s current IP routing table.
route -f : clears gateway entries from the routing table.
route -p : can be used with the add command to make a statically configured route persistent, meaning that the route will remain in a PC’s routing table even after a reboot.
Windows Commands 3
route command : Supported commands include print, add, delete, and change. The print command lists entries in a PC’s routing table. The add command adds a route entry. The delete command removes a route from the routing table, while the change command can modify an existing route.
route destination : specifies the destination host or subnet to add to a PC’s routing table.
route mask (or netmask) : used in conjunction with the destination option, specifies the subnet mask of the destination. If the destination is the IP address of a host, the netmask parameter is 255.255.255.255.
route gateway : specifies the IP address of the next-hop router used to reach the specified destination.
route metric : This option specifies the cost to reach a specified destination. If a routing table contains more than one route to reach the destination, the route with the lowest cost is selected.
if interface : forward traffic to a specified destination out of a specific interface.
pathping = combines features of ping and tracert over a period of time.
pathping -g host-list : Loose source route along host-list. Loose source routing permits you to specify a set of destinations the packet must visit in transit.
pathping -h maximum_hops : max no. of hops to search for a target.
pathping -i address : use specificed source address.
pathping - n : do not resolve addresses to hostnames.
pathping -p period : wait period of milliseconds between pings
pathping -q num_queries : no. of queries per hop.
pathping -w timeout : wait timeout milliseconds for each reply.
pathping -4/-6 : force using IPv4/IPv6.
Windows Commands 4
arp -a : displays current ARP entries in a UNIX hosts ARP table.
arp -n : displays network addresses as numbers instead of symbols.
arp -i interface : specifies that ARP command should be limited to a specific interface.
arp -d : An ARP entry for a host can be deleted with this option, in combination with the inet_addr parameter.
arp -s : used in conjunction with the hostname and eth_addr parameters, statically adds a host entry in the ARP table.
arp ifscope interface : indicates that the arp command should be limited to a specified interface.
arp hostname : is the IP address of the host to be associated with a specified MAC address.
arp eth_addr : specifies a 48-bit MAC address.
arp temp : Used in conjunction with the -s option, the temp option says that the static ARP entry is only temporary, as opposed to the default of being permanent.
arp reject : Used in conjunction with the -s option, this option says that traffic to the destination specified in the static ARP entry will be rejected, and the sender will be notified that the host is unreachable.
Linux Commands
dig : FQDN-to-IP-address resolution
host : resolving FQDNs to IP addresses
iptables UNIX command to put rules in place for packet filtering. Packet type: Specifies the type of packets the command filters. Packet
source/destination: Specifies which packets the command filters based on the source or destination of the packet. Target: Specifies what action is taken on packets matching the preceding criteria.
tcpdump : run the command with the -w flag, which causes it to save the packet data to a file for later analysis, and/or with the -r flag, which causes it to read from a saved packet file rather than to read packets from a network interface.
traceroute UNIX command can be used for the same purpose as the tracert Windows command. ex : traceroute -6 (IPv6)
netstat : display various information about current connections.
netstat -a : This option displays all of a UNIX host’s active IP-based sessions, along with the TCP and UDP ports of each
session.
netstat -p : This option shows connections for the protocol specified by protocol. In this case, protocol can be tcp, udp, tcpv6, or udpv6.
netstat -r : displays a UNIX host’s IP routing table.
netstat -s : displays statistical information for protocols such as udp, ip, icmp, igmp, ipsec, ip6, icmp6, ipsec6, rip6, and pfkey.
ping -c count : specifies no. of pings to send.
ping -D : This option sets the “don’t fragment” bit in a packet’s header. If the packet tries to cross a router that attempts to fragment the packet, the packet is dropped and an ICMP error message is returned.
ping -S srcaddr : If the UNIX host from which you are issuing the ping command has more than one interface, this option allows you to specify the source IP address from which the ICMP echo messages should be sent.
ping target_name : specifies the name or the IP address of the device to which you are sending ICMP echo messages.
Linux Commands 2
arp blackhole : the blackhole option says that traffic to the destination specified in the static ARP entry will be rejected. However, the sender is not notified.
arp -f filename : This option allows an external file to be used to import a collection of ARP entries.
route -q : q stands for quiet, suppresses any output from appearing onscreen after the route command is entered.
route -v : causes additional details about the route command’s execution to be shown onscreen.
route add : adds a route to a UNIX host’s routing table.
route delete : This option deletes a route from a UNIX host’s routing table.
route net : specifies that the next parameter is a network address.
route network : specifies the network to add or remove from a UNIX host’s routing table.
route mask : number of bits in a specified network’s subnet mask.
route gateway : is the IP address of the gateway, which is the next hop toward the specified network.
Linux Commands 3
Point-to-Point Protocol (PPP). PPP has the capability to simultaneously transmit multiple Layer 3 protocols (for example, IP and IPX) through the use of control protocols (CPs).
PPP
