Webtop asks again for authenticacion

I think you can use multi-domain SSO instead of your configuration.

multi domain SSO is used to provide authentication on only one URL:

webtop.domain.com

when a user access to app1.domain.com,

• he is redirected to https://webtop.domain.com
• after authentication, he is redirected to app1.domain.com

you can define hundreds of URLs authenticating on the same URL.

if the user access to https://webtop.domain.com, you can assign a webtop with webtop links.

My irule must be modified for to be compatible with Multi-domain SSO:

when HTTP_REQUEST {
    if { ( [set MRHSession_cookie [HTTP::cookie value "MRHSession"]] ne "" ) and ( [ACCESS::session exists -state_allow $MRHSession_cookie] ) } then {
        log local0. "URI: [HTTP::uri]"
        if { [HTTP::uri] equals "/" && ([set webtop [ACCESS::session data get -sid $MRHSession_cookie "session.assigned.webtop"]] ne "")} {
            if {[PROFILE::access domain_mode] && [URI::host [PROFILE::access primary_auth_service]] equals [HTTP::host]} {
            HTTP::redirect "/vdesk/webtop.eui?webtop=${webtop}&webtop_type=webtop_full";
            }
        }
    }
}

EDIT : I corrected the irule according to Sergi's comment about the missing

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