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ST_Wong's avatar
ST_Wong
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Jul 12, 2023

Multiple IP addresses ranges on external network

Hello, We've LTM (14.1.4.2) running for years, serving VLAN with addresses 192.168.8.0/24. Recently the same VLAN 'expanded' with another address range (192.168.31.0/23). We tried to define virtua...
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ST_Wong's avatar
ST_Wong
Icon for Cirrus rankCirrus

Hi all,

Thanks for your help.

I tried to define a VS using the new subnet address before I did anything, with destination/mask setting to. say. 192.168.31.250/23 or 192.168.31.250/255.255.254.0.   But LTM complaints the value is invalid.    I can only provide a mask of 255.255.255.255 or simply no mask at all.  

Possible to specify the correct netmask (/23) in virtual server destination ?

Thanks again.

Best Regards

JRahm's avatar
JRahm
Icon for Admin rankAdmin
Jul 13, 2023

Hi ST_Wong  the virtual server listens on a host or range of hosts as a CIDR block. So if you are trying to establish a /23 network for the virtual server to listen on, then it needs to be a valid network address to do so. If you are only wanting to listen to the 192.168.31.250 host, then you do not need to specify the mask on the destination at all. 

The virtual server is not an L3 routing table. Routes assure that traffic gets to/from the BIG-IP, the virtual server is how traffic flows through the BIG-IP.