Other Common Application Protocols
Many multimedia applications used for videoconferencing---for example CU-SeeMe, H.323 (for NetMeeting and ProShare), and RealAudio---use the TCP control channel to establish media channels. This control channel contains information that opens new media channels. Firewalls should have the capability to watch these control channels, to identify those ports that media channels use, and to open additional channels on a dynamic basis.
Table 9-1 lists the most common applications that should be supported in firewalls to have extensive
Securing Internet Access application control support:
|
Protocol |
Description |
|
Audio/Video Streaming |
|
|
CU-SeeMe by White Pine |
Application that supports live audio/videoconferencing and text chat across the Internet |
|
H.323 |
New standard in audio/videoconferencing |
|
Internet Phone by Intel |
Voice communication application above H.323 protocol stack |
|
NetMeeting by Microsoft |
Audio, video, and application sharing implemented over T.120 and H.323 |
|
RealAudio and RealVideo by Progressive Networks |
Protocol for the transmission of high-quality streaming sound and video on the Internet |
|
StreamWorks by Xing |
Protocol for the transmission of high-quality streaming sound and video on the Internet |
|
VDOLive by VDOnet |
Application for transmitting high-quality video over the Internet |
|
Information Seeking |
|
|
Archie |
Standard tool for searching Internet file servers |
|
Gopher |
Application that provides a menu-driven front-end to Internet services |
|
HTTP |
Primary protocol used to implement the WWW |
|
Network News Transfer Protocol (NNTP) |
Protocol used to transmit and receive network news |
|
Pointcast by Pointcast (HTTP) |
Protocol for viewing news in TV-like fashion |
|
Wide Area Information Servers (WAIS) |
Tool for keyword searches (based on database content) of databases on the Internet |
|
Security and Authentication |
|
|
HTTPS |
Secured (that is, encrypted) HTTP; an implementation of SSL |
|
TACACS+ |
Authentication protocol |
|
Kerberos |
Authentication service |
|
LDAP |
Standard for Internet directory services |
|
RADIUS |
A widely adopted authentication protocol |
|
Secure ID |
Protocol used by an authentication service product of Security Dynamics Technologies, Inc. |
|
Databases |
|
|
Lotus Notes |
Proprietary protocol developed by Lotus to implement its Notes application |
|
SQL Server by Microsoft |
A data replication server |
|
SQLNet Version 1 |
Oracle protocol for transmission of SQL queries |
|
SQLNet Version 2 |
Extension of SQLNet Version 1; adds support for port redirection |
|
|
|
|
Comsat |
Mail notification protocol |
|
Imap |
Internet mail access protocol |
|
POP Version 2 |
Mail protocol that allows a remote mail client to read mail from a server |
|
POP Version 3 |
Modified version of POP Version 2 |
|
SMTP |
Protocol widely used for the transmission of e-mail |
|
Other TCP and UDP Services |
|
|
Chargen |
TCP Chargen server sends a continual stream of characters until the client terminates the connection; UPD Chargen servers send a datagram containing a random number of characters in response to each datagram sent by a client |
|
Daytime |
Daytime server returns the date and the time of day in text format; can be run over TCP or UDP |
|
Discard |
Discard server discards whatever is sent to it by a client; can be run over TCP or UDP |
|
DNS |
Distributed database used by TCP/IP to map names to IP addresses |
|
Finger |
Protocol that provides information about users on a specified host |
|
FTP |
Protocol for copying files between hosts |
|
Identd (auth) |
Protocol used for user identification |
|
Internet Relay Chat (IRC) |
Protocol for online "chat" conversations over the Internet |
|
NetBIOS over TCP/IP (NBT) |
NetBIOS name, datagram, and session services encapsulated within TCP/IP |
|
Network Time synchronization Protocol (NTP) |
Protocol providing time across a network with precise clocks; implemented over TCP and UDP |
|
RAS |
Remote access service |
|
Rexec |
Protocol that provides remote execution facilities |
|
Rlogin |
Protocol that enables remote login between hosts |
|
Rsh |
Protocol that allows commands to be executed on another system |
|
Simple Network Management Protocol(SNMP) |
Protocol used for managing network resources |
|
SNMP Trap |
Notification by SNMP to the manager of some event of interest |
|
Syslog |
Protocol that allows a computer to send logs to another computer |
|
Telnet (Telecommunications Network Protocol) |
Remote terminal protocol enabling any terminal to log in to any host |
|
TFTP |
Small, simple FTP used primarily in booting diskless systems |
|
Time |
Service that returns the time of day as a binary number |
|
UNIX-to-UNIX Copy Program (UUCP) |
UNIX file-copying protocol |
|
Who |
Service that uses local broadcasts to provide information about who is logged on to the local network |
|
X11 |
Windowing system protocol |
|
Remote Procedure Call Services |
|
|
Lockmanager (nlockmgr) |
Protocol used for the transmission of lock requests |
|
Mountd |
Protocol used for the transmission of file mount requests |
|
Network File System (NFS) |
Protocol that provides transparent file access over a network |
|
Network Information Service (NIS) |
Protocol that provides a network-accessible system-administration database, widely known as the Yellow Pages |
|
Rstat |
Protocol used to obtain performance data from a remote kernel |
|
Rwall |
Protocol used to write to all users in a network |
Continue reading here: Public Versus Private IP Addresses
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