Alteon Application Switch Operating System Application Guide
Server Load Balancing
190
Document
ID:
RDWR-ALOS-V2900_AG1302
The maintenance mode command
/maint/debug/vmasp
can be used to find the processor for any
combination of source IP, source port (if VMA with source port is enabled), and destination IP (if VMA
with destination IP is enabled).
Miscellaneous Debug
When VMA with destination IP is enabled, the following message displays:
Client Network Address Translation (Proxy IP)
Network address translation (NAT) is the process of modifying IP address information in IP packet
headers while in transit across a traffic-routing device.
There are several types of NAT mechanisms, but the most common method is to hide an entire IP
address space behind a single IP address, or a small group of IP addresses. To enable correct
handling of returned packets, a many-to-one NAT mechanism must modify higher-level information
such as TCP or UDP ports in outgoing communications.
Alteon uses the many-to-one NAT mechanism to translate client IP address and port information.
Client NAT can serve several purposes, including:
•
Hiding the client IP address from the servers for increased security.
•
Solving routing issues when clients and servers belong to the same IP address space (subnet).
By using NAT on the the client IP address , traffic returning from the server is forced to pass via
Alteon.
•
Support for non-transparent proxy functionality. Alteon works as a non-transparent proxy in the
following cases:
—
When performing connection management (multiplexing).
—
When performing as an IPv4/IPv6 gateway.
Note:
Client IP address translation is mandatory for non-transparent proxy capabilities.
This section includes the following topics:
•
Client NAT for Virtual Services, page 190
•
Client NAT for Filters, page 194
•
Using a Virtual Server IP Address to NAT outbound traffic, page 194
Client NAT for Virtual Services
You can perform client NAT per virtual service based on one of the following options:
•
NAT using a proxy IP address configured on an ingress port or VLAN. For more information, see
Port or VLAN-based Proxy IP Addresses, page 191
.
•
NAT using a proxy IP address configured on an egress port or VLAN. For more information, see
Port or VLAN-based Proxy IP Addresses, page 191
.
•
NAT using a specific proxy IP address or subnet. For more information, see
Address for Virtual Service, page 192
•
NAT using a specific network class. For more information, see
>> /cfg/slb/adv/vmadip ena
Current VMA with destination IP: disabled
New VMA with destination IP: enabled
WARNING!! Changing VMA option may result in temporary disconnection of clients.
Do you want to continue? [y/n] [n]