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Rosieodonell_16's avatar
Rosieodonell_16
Icon for Cirrus rankCirrus
Feb 08, 2019

F5 webmail exchange 2016 - "Access policy evaluation is already in progress for your current session."

We recently moved over to outlook 2016. Users that are on 2010 connect fine and never have an issue. the new users that have moved over to 2016 mailboxes get the error message above in the title. When they connect, they get the following addons to their URL:

  • ?bO=1
  • sessiondata.ashxappcacheclient=1&acver=15.1.1591.8&crr=1

I have tried irules from the following devcentral questions and answers with no success:

If i have users open a browser in "InPrivate Browsing" or "Incognito" mode, they don't get the error. I have also tried the windows_10_anniversary_fix as well as all the irules on page 76 of the iapp deployment guide for exchange 2016.

Deployment guide stuff i tested and doesn't work:

when HTTP_REQUEST {

if { [HTTP::cookie exists "IsClientAppCacheEnabled"] } {

HTTP::cookie "IsClientAppCacheEnabled" False

}

}

and tried this:

when HTTP_REQUEST {

if { [HTTP::cookie exists "IsClientAppCacheEnabled"] } {

HTTP::cookie remove "IsClientAppCacheEnabled"

HTTP::cookie insert name "IsClientAppCacheEnabled" value False

}

}

I have a ticket open with F5 but they are saying oh just check the guide. not helpful. Hoping someone from the community can help me. thanks in advance!

2016
access policy
application delivery
BIG-IP Access Policy Manager (APM)
exchange
irule
iRules
security
sessions

1 Reply

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  • KeesvandenBos's avatar
    KeesvandenBos
    Icon for MVP rankMVP
    Feb 11, 2019

    Hi,

    This preload issue could be solved with this irule:

    when ACCESS_SESSION_STARTED {
    set landinguri [ACCESS::session data get session.server.landinguri]
    switch -glob $landinguri {
        "/owa/plt1.ashx?*" -
        "/owa/sessiondata.ashx?appcacheclient=1" -
        "/owa/userspecificresourceinjector.ashx?*&appcacheclient=1*" -
        "/owa/manifests/appCacheManifestHandler.ashx?owamanifest=1" {
            ACCESS::respond 403 -version "1.1" noserver "Connection" "Close"
            ACCESS::session remove
            return
        }
    }
}

    Cheers,

    Kees