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how to avoid dns caching for a few urls with a CE 507 ?

how to avoid dns caching for a few urls with a CE 507 ?


Re: how to avoid dns caching for a few urls with a CE 507 ?

The following document explains how to filter urls on the cache engine. Use the bypass commands to set up a bypass for WCCP-redirected traffic.


Re: how to avoid dns caching for a few urls with a CE 507 ?


the question regarding DNS-Caching is quite intresting. Unfortunatly I could only find informations regarding URL-Filtering in the above link. DNS caching is intressting in another environment as one has the possibility to have multiple IP-Adresses per DNS-Name (e.g. will be resolved as and the next request or in failure conditions it will be resolved as

Lets think about the following:

The CE would cache the DNS-resolution of and would cache content of A user requests The CE will send a request towards (the cached DNS-entry) to proove if the content is still valid or not. Now lets think of the possibility that has a problem and is not responding. Now the CE does not know what to do as the server is not responding. In my opinion this would cause an error (Server not available). Now let's imagine that the DNS-Server knows about the problems of and does only send the IP-adress of if is alive and if not In this case a new DNS-resolution of for prooving if the content is still valid or not will have the result and the prooving could take place and everything is fine. This problem will also occur if a new page on will be requested and the already (cached) DNS-Entry will be used to get this information and is not present.

Now my question:

How does the CE behave: Will the CE cache the DNS-resolution of a server or not?

If yes is this caching duration configurable or not.



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