Sun Rpc Inspection Overview - Cisco FirePOWER ASA 5500 series Configuration Manual

Sun RPC Inspection

Sun RPC Inspection Overview

The Sun RPC inspection engine enables or disables application inspection for the Sun RPC protocol. Sun
RPC is used by NFS and NIS. Sun RPC services can run on any port. When a client attempts to access
an Sun RPC service on a server, it must learn the port that service is running on. It does this by querying
the port mapper process, usually rpcbind, on the well-known port of 111.
The client sends the Sun RPC program number of the service and the port mapper process responds with
the port number of the service. The client sends its Sun RPC queries to the server, specifying the port
identified by the port mapper process. When the server replies, the security appliance intercepts this
packet and opens both embryonic TCP and UDP connections on that port.
NAT or PAT of Sun RPC payload information is not supported.
Note
Managing Sun RPC Services
Use the Sun RPC services table to control Sun RPC traffic through the security appliance based on
established Sun RPC sessions. To create entries in the Sun RPC services table, use the sunrpc-server
command in global configuration mode:
hostname(config)# sunrpc-server interface_name ip_address mask service service_type
protocol {tcp | udp} port[-port] timeout hh:mm:ss
You can use this command to specify the timeout after which the pinhole that was opened by Sun RPC
application inspection will be closed. For example, to create a timeout of 30 minutes to the Sun RPC
server with the IP address 192.168.100.2, enter the following command:
hostname(config)# sunrpc-server inside 192.168.100.2 255.255.255.255 service 100003
protocol tcp 111 timeout 00:30:00
This command specifies that the pinhole that was opened by Sun RPC application inspection will be
closed after 30 minutes. In this example, the Sun RPC server is on the inside interface using TCP port
111. You can also specify UDP, a different port number, or a range of ports. To specify a range of ports,
separate the starting and ending port numbers in the range with a hyphen (for example, 111-113).
The service type identifies the mapping between a specific service type and the port number used for the
service. To determine the service type, which in this example is 100003, use the sunrpcinfo command
at the UNIX or Linux command line on the Sun RPC server machine.
To clear the Sun RPC configuration, enter the following command.
hostname(config)# clear configure sunrpc-server
This removes the configuration performed using the sunrpc-server command. The sunrpc-server
command allows pinholes to be created with a specified timeout.
To clear the active Sun RPC services, enter the following command:
hostname(config)# clear sunrpc-server active
This clears the pinholes that are opened by Sun RPC application inspection for specific services, such
as NFS or NIS.
Cisco Security Appliance Command Line Configuration Guide
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Chapter 25 Configuring Application Layer Protocol Inspection
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