HP MSR2000/3000/4000 Router Series Layer 3 - IP Services Command Reference

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Syntax
nat alg { all | dns | ftp | h323 | icmp-error | rtsp | sip | tftp }
undo nat alg { all | dns | ftp | h323 | icmp-error | rtsp | sip | tftp }
Default
NAT ALG for all protocols is enabled.
Views
System view
Predefined user roles
network-admin
Parameters
all: Enables NAT with ALG for all supported protocols.
dns: Enables NAT with ALG for DNS.
ftp: Enables NAT with ALG for FTP.
h123: Enables NAT with ALG for H123.
icmp-error: Enables NAT with ALG for ICMP error packets.
rtsp: Enables NAT with ALG for RTSP.
sip: Enables NAT with ALG for SIP.
tftp: Enables NAT with ALG for TFTP.
Usage guidelines
Use ALG with NAT to translate the payload information to ensure the establishment of data connections.
NAT translates IP address and port information in packet headers, and ALG processes the fields in
application layer payloads. The packet payloads of some protocols might contain IP address or port
information for connection establishment. If this information is not translated, problems might occur. For
example, an FTP application involves both data connection and control connection. The data connection
establishment dynamically depends on the payload information of the control connection.
Examples
# Enable NAT with ALG for FTP.
<Sysname> system-view
[Sysname] nat alg ftp
Related commands
display nat all
nat dns-map
Use nat dns-map to map the domain name of an internal server to the public IP address, public port
number, and protocol type of the server.
Use undo nat dns-map to remove a DNS mapping for NAT.
Syntax
nat dns-map domain domain-name protocol pro-type { interface interface-type interface-number | ip
global-ip } port global-port