Command Line Interface Reference Guide > The SLB Configuration Menu > /cfg/slb/virt <virtual server ID> Virtual Server SLB Configuration
/cfg/slb/virt <virtual server ID>
Virtual Server SLB Configuration
Use this menu to configure the virtual servers which are the target for client requests for SLB. The minimum required parameters for virtual servers are:
*Creating a virtual server IP address
*Adding a TCP or UDP port and real server group
*Enabling the virtual server (disabled by default)
Note: When you set the ID while configuring objects such as real servers, virtual servers, or groups, ensure that you also specify at least one additional setting such as the description. Otherwise, Alteon does not treat such an object as created and removes it on apply.
 
[Virtual Server 1 Menu]
service - Virtual Service Menu
ipver - Set IP version
vip - Set IP addr of virtual server
vname - Set name of virtual server
srcnet - Set Source Network Class
dname - Set domain name of virtual server
cont - Set BW Contract
weight - Set Global SLB weight for virtual server
avail - Set Global SLB availability for virtual server
avpersis - Enable/disable GSLB availability persistence
nat - Set NAT address for VIP
wanlink - Set WAN Link for this virtual server
addrule - Add Global SLB rule to domain
remrule - Remove Global SLB rule from domain
rtsrcmac - Enable/disable return to source mac address
hagrp - Set HA group
remhagrp - Remove virt from HA group
layer3 - Enable/disable layer 3 only balancing
creset - Enable/disable client connection reset for invalid VPORT
ena - Enable virtual server
dis - Disable virtual server
del - Delete virtual server
cur - Display current virtual configuration
 
Virtual Server Configuration Menu Options (/cfg/slb/virt)  
Command Syntax and Usage
service <virtual port or name>
 
Displays the Virtual Server Service menu. The virtual port name can be a well-known port name, such as HTTP, FTP, the service number, and so on. To view this menu and the list of well-known ports, see /cfg/slb/virt <server number> /service <virtual port or application name> Virtual Server Service Configuration.
Values:1, 10 – 65534
ipver <IP version (v4 or v6)>
 
Specifies the type of IP address for the virtual server.
Values: v4, v6
Default: v4
vip <virtual server IP address for IPv4 or IPv6>
 
Specifies the IP version and address of the virtual server. The virtual server created within Alteon responds to ARPs and pings from network ports as if it was a normal server. Client requests directed to the virtual server’s IP address are balanced among the real servers available to it through real server group assignments.
dname <64 character domain name> | none
 
Specifies the domain name for this virtual server. When configured the domain name is used for:
*DNS resolution for global load balancing.
Additional domains can be defined on the same virtual server by attaching multiple DNS (GSLB) rules, each with a different domain.
*HTTP/S health check, if the health check host command is set to inherit.
The domain name typically includes the name of the company or organization, and the Internet group code (.com, .edu, .gov, .org, and so on). For example, “foocorp.com”.
It does not include the hostname portion (www, www2, ftp, and so on).
To define the hostname, see the hname command in this table. To clear the dname, specify the name as none.
Values: 1 – 64 alphanumeric characters.
vname <32 character virtual server name> | none
 
Specifies a descriptive name for the virtual server.
Maximum characters: 128
srcnet <32 character source network class>|none
 
Sets the source network class for this virtual server. For more information on network classes, see /cfg/slb/nwclss <network class ID> Network Class Configuration Menu.
Values: 1 – 32 characters
cont <BWM contract (1-1024)>
 
Specifies a bandwidth management contract for traffic to the virtual server. By default, all services under this virtual server are assigned this contract. You can also define the contract at the virtual service level with the /cfg/slb/virt <number>/service <number>/cont command.
All the frames that match this virtual server services are assigned this contract if the previously assigned contract for the frame has lower or equal precedence to the virtual server contract.
Default: 1024
weight <1-48>
 
Specifies the global server weight for the virtual server.
The higher the weight value, the more connections that are directed to the local site.
The response time of this site is divided by this weight before the best site is assigned to a client. Remote site response times are divided by the real server weight before selection occurs.
Values: 1 – 48
Default: 1
avail <1-48>
 
Specifies the Global Server Load Balancing (GSLB) priority for the virtual server.
Rules that use availability as the primary metric handle failures by selecting the server with the next highest score compared to that of the server that failed, and begin forwarding requests to that server. If the server that failed becomes operational again, that server regains precedence and requests are routed to it once more.
Values: 1 – 48
Default: 1
avpersis enable|disable
 
Specifies whether a server that failed and became operational again, can (disable) or cannot (enable) regain precedence from the recovery server.
Ensuring that the former primary server does not regain precedence is achieved by assigning the highest possible availability value (48) to the server that takes over after a failure. If this new primary server fails, its original availability value is restored and the next server in the list gains the higher precedence.
Default: disable
nat
Sets the NAT address for the virtual server. For use when an Alteon sits behind a NAT device.
Two Alteons, each behind a separate NAT device, connect using the IP address of each other’s NAT device for DSSP communication. When an Alteon performs DNS resolution, the DNS response must include the public (NAT) address of the service, not the internal virtual IP address. When Alteons are installed between NAT devices:
*Alteon must be aware of the public (NAT) address for each of its virtual IP addresses.
*The remote real server must always be configured using public (NAT) addresses.
wanlink
 
Specifies the WAN Link via which this virtual server can be accessed, when the application can be accessed via multiple WAN links (multihoming).
WAN link load balancing enables Alteon to provide gigabit connectivity from corporate resources to multiple ISP links to the Internet.
Alteon acts as a front-end to the WAN links, interpreting user session requests and distributing them among the available WAN links.
addrule <rule, 1-2048>
 
Adds a GSLB rule to the virtual server domain.
A DNS rule must always be selected to define the metrics Alteon uses to select a site. Additional DNS rules can be selected to allow for:
*Multiple domains that should be resolved to the same service IP.
*Different selection rules per time of day.
Note: The maximum number of rules that you can configure depends on the type of platform and the number of CUs configured, as follows:
*Standalone: 2048
*VA: 2048
*vADC with less than 5 CUs: 512
*vADC with 5 – 10 CUs: 1024
*vADC with 11 or more CUs: 2048
Default: rule 1
remrule <rule, 1-2048>
 
Removes a GSLB rule from the domain.
rtsrcmac disable|enable
 
Specifies how to forward response traffic to the client.
Values:
*enable — Alteon returns the response traffic (towards the client) to the MAC address from which the request arrived. This is saved in the session entry when the session is created (controlled by sessrts). Alteon bypasses all routing configuration in the device.
*disable — Alteon returns the traffic using the routing table.
Default: disable
Note: When rtsrcmac is enabled, you must enable Direct Access Mode (DAM) in a virtual server service configuration (/cfg/slb/ virt <server id>/service <virtual port or application name>/direct ena). For a service with layer3 enabled, make sure that rtsrcmac is disabled.
hagrp
 
Sets the high availability service group for this virtual service.
remhagrp
 
Removes this virtual service from a high availability service group.
layer3 <enable|disable>
 
Normally, use the client IP address with the client Layer 4 port number to produce a session identifier. When enabled, Alteon uses only the client IP address as the session identifier.
This option is necessary for some server applications where state information about the client system is divided across different simultaneous connections, and also in applications where TCP fragments are generated.
If the real server to which the client is assigned becomes unavailable, the Layer 4 software allows the client to connect to a different server.
Values:
*enable — Enables Layer 3-only load balancing. Alteon uses only the client IP address as the session identifier. It associates all the connections from the same client with the same real server while any connection exists between them.
*disable — Enables Layer 4 load balancing. Alteon uses the client IP address with the client Layer 4 port number to produce a session identifier.
Default: disable
creset enable|disable
 
Specifies whether to drop or reset connections to an invalid virtual port.
Values:
Default: disable
preempt enable|disable
 
Enables or disables GSLB failover preemption.
ena
 
Specifies whether to enable the virtual server. This option activates the virtual server so that it can service client requests sent to its defined IP address.
Default: disable
dis
 
This option disables the virtual server so that it no longer services client requests.
del
 
This command removes this virtual server from operation and deletes it from the Layer 4 switching software configuration.
Note: Use this command with caution, as it deletes the options that have been set for this virtual server.
cur
 
Displays the current configuration of the specified virtual server.