VIP in SLB can not connect to the real servers

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Nov 4th, 2008
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I have this situation.

Three server farm, each with two real server, which should be accessed by their Virtual IP addresses in their respective ports, i.e. client request should be natted by the SLB to correspond to the real servers. This means that, clients are in different VLANs from the one with real servers. So clients connects by using Virtual IP addresses, and expected to be natted to the real one. Below is the sample of my configurations;

Server Farm Configurations


ip slb serverfarm SF_1

nat server

access Vlan21



weight 1

faildetect numconns 1 numclients 1




weight 1

faildetect numconns 1 numclients 1



Virtual Server Configurations


ip slb vserver VS_TCP1

virtual udp 69

serverfarm SF_1

access Vlan1

replicate casa 1026 password xxx

inservice standby FW_Side


Now with this configuration, i need to achieve two things;

1. The virtual server needs to be configured to connect to the couple of ports with only one Virtual IP address.

2.The clients, who are in VLAN one, should use the virtual IP address, i.e., to connect to the real servers in ports 20/21, 25 and 69 and any other specified after step one is configured for the couple of ports.

Any support, will highly be appreciated.



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Anonymous (not verified) Tue, 11/11/2008 - 15:28
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The Cisco IOS Server Load Balancing (SLB) feature allows the user to define a virtual server that represents a cluster of real servers, known as a server farm. When a client initiates a connection to the virtual server, the Cisco IOS SLB load balances the connection to a chosen real server, which depends on the configured load-balance algorithm or predictor.

Configuring Real Servers and Server Farms:


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