If your using Micollab softphone NextGen all the sip signaling is
encrypted with TLS so the Fortigate won't be able to modify the packet.
Because Mitel have is own SIP proxy Firewall (Mitel Border Gateway) the
SIP ALG only cause trouble and must be d...
You should always use teleworker mode on the MiCollab softphone even on
VPN, but when you're connected on VPN the MiCollab FQDN server must
resolve to your internal Micollab and not the MBG, then you need o
create a firewall rule VPN interface to you...
