Transcript CS4550 Computer Networks II Topics In Applications Ref: Feit Chap

CS4550
Computer Networks II
Topics In Applications
Ref: Feit Chap 13-20
Tanenbaum Chap 7
1
General Architecture
Clients, requestor programs
From Port 23
Servers, demon, reply peer
To port 23
TCP UDP
From
Protocol 6
IP
DL and physical
TCP UDP
To protocol 6
IP
DL and physical
Common Tools
Ping
Echo 7/udp
netstat
time 13/udp
traceroute tracert
quote 17/udp
TELNET
First Application
Connect as a terminal to a networked host
Terminal emulation
Telnet to selected port
Commands
Connect as a terminal to a networked host
NVT - Network Virtual Terminal
Solves Multi vendor problem
NVT code - 7 bit USASCII 128 characters
Line Format- half duplex, stop and wait, <CR><LF>
Command Format - Interpret As Command (IAC)
Escape character IAC = 255 note 8’th bit set
IAC
Command
option
255
251
24
will
terminal type
Terminal emulation
Connect to a selected port
Telnet cs.nps.navy.mil 7
echo service
telnet cs.nps.navy.mil 13
time of day service
telnet cs.nps.navy.mil 80
www service
telnet cs.nps.navy.mil 25 mail service
type help
Telnet Commands
get a list of commands
Wolf> telnet
telnet > ?