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Lee_Sutcliffe_5's avatar
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Jun 24, 2015

VS Precedence


I have a question relating to VS precedence and which VS would process the packet in the following example:

Packet  - destination IP  > destination port > TCP/80

 protocol tcp

 protocol udp

My understanding having read is that there is a higher emphasis on the VS with the longest subnet match.

However, in the in above example, this would be VIP-B - but the protocol for this VS is UDP.

Would VIP-B process the request and subsequently drop traffic - or is the BigIP intelligent enough to match on a VS with a lower precedence, but one that has the correct protocol configured?

Many thanks


2 Replies

  • Hi Lee, When a listener lookup occurs, the precedence linked above matches as expected for all matching traffic types. For example, consider the following three virtuals:


    1. *All Protocols
    2. *UDP
    3. *TCP

    If you send an http request to, the vip 1 will receive the traffic. If you send an http request to, vip 3 will receive the traffic. If you delete vip 1 and retry an http request to, it will bypass vip 2 because of a protocol mismatch and match vip 3.


    So to answer your question, yes, the precedence matters first, but only when the virtual is capable of handling that traffic. A UDP virtual, even with a longer match, isn't capable of handling TCP traffic, so it doesn't apply.


  • Hi Jason,


    Thanks for your explanation, that question has been bugging me for a while!