NAT supports many traffic types. The Remote Access exam includes questions on both the supported
and unsupported types. Let’s take a look at these types now.
Supported Traffic Types
NAT supports the following traffic types:
TCP traffic that does not carry source and destination addresses in an application stream
UDP traffic that does not carry source and destination addresses in an application stream
Hypertext Transfer Protocol (HTTP)
Trivial File Transfer Protocol (TFTP)
File Transfer Protocol (
FTP PORT
and
PASV
commands)
Archie, which provides lists of anonymous FTP archives
Finger, a software tool for determining whether a person has an account at a particular
Internet site
Network Time Protocol (NTP)
Network File System (NFS)
rlogin
,
rsh
,
rcp
(TCP, Telnet, and Unix entities to ensure the reliable delivery of data)
NAT-supported protocols that carry the IP address in the application stream include:
Internet Control Message Protocol (ICMP)
NetBIOS over TCP (datagram, name, and session services)
Progressive Networks’s RealAudio
CUseeMe Networks CUseeMe
Xing Technology’s StreamWorks
DNS “A” and “PTR” queries
H.323 in IOS versions 12.0(1)/12.0(1)T or later
Microsoft’s NetMeeting (IOS versions 12.0(1)/12.0(1)T or later)
VDOnet’s VDOLive – IOS versions 11.3(4)/11.3(4)T or later
Microsoft’s VXtreme – IOS versions 11.3(4)/11.3(4)T or later
IP Multicast – IOS version 12.0(1)T or later, source address translation only
Point-to-Point Tunneling Protocol (PPTP) support with Port Address Translation (IOS
version 12.1(2)T or later)
Skinny Client Control Protocol, IP Phone to Cisco CallManager (IOS version 12.1(5)T or later)
Unsupported Traffic Types
NAT does not support some traffic types, including the following:
Routing table updates
DNS zone transfers
BOOTP and DHCP
Talk
Ntalk
Simple Network Management Protocol (SNMP)
NetShow