Virtual Server creation

I tried to change mask via modify command but got the same error.

[root@f5:Active] config tmsh

root@f5(Active)(tmos) list ltm virtual vs_http_sandeep

ltm virtual vs_http_sandeep { destination 172.29.0.251:http ip-protocol tcp mask 255.255.255.255 pool CCE-Tomcat_pool profiles { CCE-Tomcat_lan-optimized_tcp_profile { } } snat automap }

root@f5(Active)(tmos) modify ltm virtual vs_http_sandeep destination 172.29.0.251:80 mask 255.255.254.0 translate-address enabled

01070348:3: Virtual Server vs_http_sandeep destination 172.29.0.251 and netmask 255.255.254.0 are not valid.

root@f5(Active)(tmos) modify ltm virtual vs_http_sandeep destination 172.29.0.251:80 mask 255.255.254.0

01070348:3: Virtual Server vs_http_sandeep destination 172.29.0.251 and netmask 255.255.254.0 are not valid.

Concerning the Network Interface for in and out, I do not know how to create.

When I opened "Network->Interface->Statistics" I can see there are 3 interfaces:

Name: mgmt Status: UP (I can Bits in and out, Packets in and out)

Name:1.1 Status:Uninitialized (No Bits and No Packets)

Name:1.2 Status:Uninitialized (No Bits and No Packets)

Above interface inherited from VMPlayer side as I can see 3 network adapters when I open VmPlayer ->Manage -> Virtual machines setting.

First Network Adapter : Bridge (Automatic) Second Network Adapter : Host Only Second Network Adapter : Host Only