Network Address Translation Support; Device Located Behind Nat - AudioCodes Mediant 800B User Manual

Parameter
Index
Host Or IP
CLI: host
[NFSServers_HostOrIP]
Root Path
CLI: root-path
[NFSServers_RootPath]
NFS Version
CLI: version
[NFSServers_NfsVersion]
Authentication Type
CLI: authentication-type
[NFSServers_AuthType]
User ID
CLI: uid
[NFSServers_UID]
Group ID
CLI: gid
[NFSServers_GID]
VLAN Type
CLI: vlan-type
[NFSServers_VlanType]

12.11 Network Address Translation Support

Network Address Translation (NAT) is a mechanism that maps internal IP addresses (and
ports) used within a private network to global IP addresses and vice versa, providing
transparent routing to end hosts. The primary advantages of NAT include (1) reduction in
the number of global IP addresses required in a private network (global IP addresses are
only used to connect to the Internet) and (2) better network security by hiding the internal
architecture.
The design of SIP creates a problem for VoIP traffic to pass through NAT. SIP uses IP
addresses and port numbers in its message body. However, the NAT server is unable to
modify the SIP messages and thus, can't change local addresses to global addresses.
This section discusses the device's solutions for overcoming NAT traversal issues.

12.11.1 Device Located behind NAT

Two different streams traverse through NAT - signaling and media. A device located
behind a NAT that initiates a signaling path has problems receiving incoming signaling
responses as they are blocked by the NAT server. Therefore, the initiating device must
inform the receiving device where to send the media. To resolve this NAT problem, the
following solutions are provided by the device, listed in priority of the selected method used
by the device:
User's Manual
Defines an index number for the new table record.
Note: Each table row must be configured with a unique index.
The domain name or IP address of the NFS server. If a domain name is
provided, a DNS server must be configured.
Path to the root of the remote file system in the format: /[path]. For
example, '/audio'.
NFS version used to access the remote file system.

[2] NFS Version 2

[3] NFS Version 3 (default)
Authentication method used for accessing the remote file system.

[0] Null

[1] Unix (default)
User ID used in authentication when using Unix.
The valid range is 0 to 65537. The default is 0.
Group ID used in authentication when using Unix.
The valid range is 0 to 65537. The default is 1.
The VLAN type for accessing the remote file system.

[0] OAMP

[1] Media (default)
Note: This parameter applies only if VLANs are enabled or if Multiple
IPs is configured (see ''Configuring IP Network Interfaces'' on page
115).
134
Mediant 800B Gateway and E-SBC
Description
Document #: LTRT-10286