Bug ID 1620785: F5 cache mechanism relies only on Last-Modified/If-Modified-Since headers and ignores the etag/If-None-Match headers

Last Modified: Nov 20, 2024

Affected Product(s):
BIG-IP LTM(all modules)

Known Affected Versions:
17.1.1, 17.1.1.1, 17.1.1.2, 17.1.1.3, 17.1.1.4

Opened: Jul 25, 2024

Severity: 4-Minor

Symptoms

-- Server has a document x with etag - AAAA -- When the client requests for x through BIG-IP, BIG-IP caches it and responds with 200 OK. -- Document on Server changes; new etag is BBBB and cache in BIG-IP is expired -- Clients sending requests with If None-Match: BBBB, should receive 304 with BBBB response but receiving 200 OK with AAAA.

Impact

BIG-IP serves old documents when requested with etag of the latest document

Conditions

-- Client having access to the server directly and through BIG-IP with cache enabled. (Or) -- Deployment containing two BIG-IPs with caching enabled one at a time.

Workaround

When HTTP_REQUEST_RELEASE { if { [HTTP::header exists If-None-Match] && [HTTP::header exists ETag] }{ HTTP::header remove If-None-Match } }

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips