SEM1 Flashcards
FTP Port Numbers protocol
20/21 TCP
SSH port port
22 TCP
Telnet port
23 TCP
SMTP port
Simple Mail Transfer protocol | 25| TCP
DNS port
Domain Name system| 53 | UDP and TCP
DHCP port
Dynamic Host Configuration Protocol| 67 (server) 68 (client) | UDP
HTTP port
Hyper text Transfer protocol | 80 | TCP
POP3
Post office protocol| 110| TCP
IMAP
Internet message access protocol | 143 | TCP
SNMP
Simple Network Management Protocol | 161 | UDP
HTTPS
Hyper Text Transfer Protocol Secure | 443 | TCP
IMAP description
Internet message access protocol |
Messages stay on the server until the client deletes them
POP3 description
pop3 by default deletes messages after they are downloaded
TFTP port
Trivial File Transfer protocol | 69 | UDP
IPV6 address types
link local: FE80 or / 10 reserved 1111 1110 10 (FE80) links for two devices on the same network, internal
Global Unicast: routable on the web
Multicast: FF00::/8
Private IP adress range class A
10.0.0.0 /8 255.0.0.0
P IP address range class B
172.16.0.0 /12 255.240.0.0
Pri address range class C
192.168.0.0/ 16 255.255.0.0
Class A range
0-127.255.255.255 first bit must be 0 /8
Class B range
128-191.255… first two bits must be 10 /16
Class C range
192-223.255… first three bits must be 110 /24
Multicast range
224-239.255.. first 4 bits 1110
experimental range
240-255.255.. first 4 bits are 1111
IPV6 address char
128 bits represented by 8 blocks of 4 hexadecimal chars
IPV4 char
0.0.0.0 - 255.255.255.255 /
32 bits
network utilization terms
bandwidth: theoretical capacity of the network
Throughput: actual measure of data moving through interfaces
Goodput: throughput- overhead
Describe the datalink layers sublayers
Link local control: interfaces with upperlayers to translate layer 2 to layer 3
MAC: interfaces with physical layer to tranlate packets to bits, in charge of encapsulation. customized encapsulation based on type of media being traversed
IPV6 IP4 simeltaneous usage techniques
dual stack: computers are equipped to process both at the network layer
tunneling: ipv6 is tunnelled over IPv4 protocols
translation:
collision mitigation
carries sense mutiple access collision avoidance: wireless
CSMA collision detection is wired
what two criteria are used t ohelp select a network medium
the distance the network med can carry a signal
The environment in which the medium will be installed
What is a shell and kernel
A shell interacts with the user and the kernel, it is the outer layer, usually a GUI interface
Ther kernel interacts with the hadware and the shell, users may adjust the kernel through CLI
CTRL-C
exits congif and goes back to exec, when in setup aborts back to command prompt
ctrl-z
EXITS any config and goes back to priv exec
CTRL -SHIF-6
break from DNS tracerts and pings
Hostname chars
-start with a letter
- contain no spaces
end with a letter or digit
use only letter digits and dashes
be less than 64 chars
command to ecrypt all passwords
service-password-encryption
SVI
Switch virtual interface: describes the vlan 1 which can be used to manage switches via in-band methods such as ssh an telnet
IANA
Internet assigned numbers authority assigns protocol numbers ( registered ports) , domain names, and blocks IP addresses for RIRs (regional internet registries)
Well known port number range
0-1023
ipv6 improvemetns
simpler header with fewer fields for efficent packet handling, larger payload for increased throughput, way more address space, eliminates the need for NAT
Storage on routers types
NVRAM, non vol storage for startup config file
Flash: non vol computer memory storage used for perm stor, contains the ios, logfiles, voice config files, html files, backup configs.
ROM: POST teset, limited ios as backup if full ios corrupted of deleted, bootup information
RAM: running config, ios image, routing table arp cache, packet buffer. All temp storage
router boot process
- POST, then load bootstrap
- locate and load cisco ios software
- locate and load the startup config or enter setup mode
post
power on self test, first in router bootup process. Checks the hardware components to ensure router is functioning.
bootstrap
goes into actio after POST, get loaded from ROM into ram, main purpose is to locate the ios and load it into ram. Also loads the startup configuration file from nvram to ram.
test-net address range
198.51.100/203.0.113/192.0.02/ all /24s
link-local ipv4
169.254.0.0/16 this adress is also a sign that dhcp may not be working properly
SLAAC
Stateles address autoconfig, uses icmpv6 ,no central server, uses the routing prefix and clients own eui 64 address
data link layer
accept layer 3 packets and package them to frames
perpare network data for layer 1
allowing upper layers to access media
error detection
min and max frame sizes
1518: bigger considered giant 64: less considered a runt
What is needed to scale a network
network documentation, device inventory, budget, traffic analysis
sercutiy commands to lock down a router
service-password-encryption
security-passwords min=length
login block-for t secs attempts n within tsecs
exec-timeout
enable ssh
step 1: give the router a unique host name and configure the ip domain name
2: keys must be generated for router to encrypt ssh traffic. crypto generate rsa gen-keys
3: create a local database username in global config
4: enable ssh in the line vty, login local, transport input ssh
th router is now ready to use ssh
