Last Modified: Oct 06, 2020
See more info
Known Affected Versions:
11.4.1, 11.5.0, 11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.10, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.5.3 HF2, 11.5.4, 11.5.4 HF1, 11.5.4 HF2, 11.5.4 HF3, 11.5.4 HF4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5, 11.6.0 HF6, 11.6.0 HF7, 11.6.0 HF8, 12.0.0, 12.0.0 HF1, 12.0.0 HF2
5.1.0, 12.1.0, 12.0.0 HF3, 11.6.1
Opened: Aug 07, 2015
Recent changes in the TLS clients to only use perfect forward secrecy (PFS) ciphersuites in default configuration may degrade TLS handshake rate on BIG-IP, may cause higher CPU utilization on the BIG-IP, or both. An example of a recent change is Apple iOS's App Transport Security changes to only enable ECDH ephemeral ciphersuites (the ciphersuites with the ECDHE suffix).
With this improvement, the TLS handshake rate with a ciphersuite ECDHE-RSA-AES128-GCM-SHA256 is expected to be ~50% higher on hardware platforms without Intel Cave Creek acceleration (released in 2015 and earlier). Internal testing has shown variations in the improvement between 20% and 80% with this enhancement. The comparison is against the current 12.0.x (or 11.6.x) release. The performance of ECDSA with P-256 was also improved. Conversely, previous versions of the BIG-IP will have correspondingly lower performance, or worse for older releases.
Large portion of TLS client only offers *ECDHE* ciphersuites in their TLS CLientHello, the average size of the TLS session is small (e.g. in kilobytes), and the TLS session resumption is not used. In other words, the conditions such that the TLS handshakes likely negotiate ECDHE ciphersuites with short sessions.
Order ciphersuite selection so that ECDH ciphersuites are least preferred. One method to accomplish this is to ensure that the clientssl profile's cipherstring contains 'ecdhe:ecdhe_ecdsa' at the end of the list. This will only matter/needed when non-PFS cipherssuites are allowed in the profile and are offered by the client.
Performance improvements for P-256 ECDH and ECDSA algorithms.