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kridsana_52318's avatar
kridsana_52318
Icon for Nimbostratus rankNimbostratus
Jul 10, 2013

VLAN-Group virtual server problem

Hi

 

 

I've a trouble with some problem. I access virtual server but pool member doesn't respond SYN packet. Let's see packet flow

 

Assume client ip : x .......virtual server : y.......... member : z (x,z is in the same vlan) z is mail server y is typical virtual server with no SNAT

 

 

x ---> y SYN

 

y <--- x SYN+ACK

 

x ---> y ACK

 

x ---> z SYN

 

x----> z SYN

 

x ----> z SYN

 

z <---- x RST

 

 

This system is use VLAN-Group. Is this flow is properly (client handshake with VS then client handshake with member) ?

 

I didn't see virtual server handshake with member. Is this properly for VLAN-Group ?

 

So x can connect z if bypass BIG-IP. and BIG-IP can connect z directly. but x can't connect z via virtual server y

 

Which cause that can happen? Is this Asymmetric routing problem even though I use VLAN-Group?

 

 

Thank you

 

 

config
design

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  • What_Lies_Bene1's avatar
    What_Lies_Bene1
    Icon for Cirrostratus rankCirrostratus
    Sep 02, 2013

    I'm not sure this is a VLAN Group issue, it seems more likely it's a routing issue on the server side. If x to z works that suggests the real server doesn't have a route back to the client back via the F5. You either need to change the routing on the server so it routes responses to the client back through the F5 or enable SNAT on the VS.