The cache is built up as a table, where each column specifies a certificate issuer (a CA) and for how long the response from this issuer will stay valid. You can specify a limit of the cache size, either in terms of memory or in number of responses or both. When either limit is reached, the next expired response (or the response that is the next to expire) gets replaced.
In the OCSP configuration file, specify the cache size and each row in the table as follows:
ocsp.cache.maxsize=<maxsize>[K|M|G]
ocsp.cache.maxnum=<maxnum>[K|M|G]
ocsp.cache.contents.<#>.issuermatch=<attributes>
ocsp.cache.contents.<#>.expiresafter=<time expr>
ocsp.cache.renewing.<#>.issuermatch=<attributes>
ocsp.cache.renewing.<#>.updatemargin=<margin time>
ocsp.cache.renewing.client.<clientspec>
Description of constants and values:
| Constants and Values | Description |
|---|
<maxsize>
| Replace <maxsize> with the maximum size of the cache, in bytes. You can use K, M or G when you specify the size. K=1024, M=K2 and G=K3. Default: 128M |
<maxnum>
| Replace <maxnum> with the maximum number of responses. You can use K, M or G when you specify the number. K=1000, M=K2 and G=K3. Default: 10K |
<#> | Replace <#> with a sequence number. |
<attributes>
| Replace <attributes> with the attributes to use for a match. This is to specify for which issuer the responses shall be cached. If the issuer cannot be matched with the configuration, the response will not be added to the cache. |
<time expr>
| Replace <time expr> with a time period expression (short form), specified according to ISO 8601 Representation of dates and times. One expiresafter parameter is required for each configured issuermatch parameter After this amount of time (or when nextUpdate is passed) the response will expire. |
<margin time> | Replace <margin time> with a time period expression (short form), specified according to ISO 8601 Representation of dates and times. Specifies the amount of time before the expiration time when a cached response should be refreshed with a new refresh request. |
<clientspec> | The refresh requests will be carried out by the back end OCSP client, which by default will use the settings you made in section "Specify OCSP client request" in Back end client section. You may override any of these settings by adding a new specification here. Use the same syntax as described for the back end client (see Back end client section) but replace ocsp.client with ocsp.cache.renewing.client. |
Example:
ocsp.cache.maxsize=10K
ocsp.cache.contents.1.issuermatch=*
ocsp.cache.contents.1.expiresafter=PT4M
ocsp.cache.renewing.1.issuermatch=*,c=se
ocsp.cache.renewing.1.updatemargin=PT1M
ocsp.cache.renewing.client.response.notolderthan=PT15S
