Beginning with Lotus Domino 6.0.1, Domino uses Entity tags (Etags) for cache validation.
Entity tags are only supported by HTTP/1.1. The Domino server sends an entity tag, which is a base-64 encoded strings of characters, in an ETag header for all cacheable responses because the server uses HTTP/1.1 for all responses. If the client is an HTTP/1.0 browser, then the ETag header is ignored and conditional GET's from that browser contain only the Last-Modified date. You can disable ETags for diagnostic purposes.
This helps control cache validation.
A value of 1 DISABLES ETags X-Domino-CacheValidationWithETagReason X-Domino-CacheValidationWithLastModifiedReason X-Domino-UserName X-Domino-DesignLastModified X-Domino-DatabaseLastModified X-Domino-DocumentLastModified X-Domino-AppSpecifiedLastMod X-Domino-CacheStrategyFlags X-Domino-ComputeEvalInfoFlags X-Domino-EvalInfoFlags X-Domino-ETag-Decoded X-Domino-ETag-Version X-Domino-ETag-StrategyFlags X-Domino-ETag-DesignLastModified X-Domino-ETag-DatabaseLastModified X-Domino-ETag-DocumentLastModified X-Domino-ETag-DocumentUNID X-Domino-ETag-UserName Recommendation: Always leave ETags enabled. Completely remove any reference to DominoDisableETags from NOTES.INI.