For more information regarding the security incident at F5, the actions we are taking to address it, and our ongoing efforts to protect our customers, click here.

Forum Discussion

jwlarger's avatar
jwlarger
Icon for Cirrus rankCirrus
Sep 23, 2021

During which event is SNI evaluated?

Where in the event flow is SNI evaluated? And would it interfere with an iRule that fired on the same event?   i.e. CLIENT_ACCEPTED CLIENTSSL_HANDSHAKE CLIENTSSL_CLIENTCERT CLIENTSSL_CLIENTH...
application delivery
events
LTM
sni
TMOS
Daniel_Wolf's avatar
Daniel_Wolf
Icon for MVP rankMVP
Sep 24, 2021

Hi ,

 

the earliest event you can evaluate the SNI is CLIENTSSL_CLIENTHELLO. Please see this diagram at packetpushers: https://packetpushers.net/f5-networks-irule-event-order-https/

It describes the order of iRule events in a HTTPS connection.

 

How will it interfere when there is an iRule that uses the same event?

Read this devcentral article: https://devcentral.f5.com/s/articles/getting-started-with-irules-events-priorities-20402, pay attention to the section headlined "What happens if I have the same event in multiple iRules on a virtual server?".

 

KR

Daniel