Overview of Exchange 2013 Architecture Transport components shipping with Exchange 2013 Mail Routing Scenarios Transport High Availability SMTP Client Submission

DAG MBX CAS HUBUM Protocols; API; BizLogic Auth; Proxy; Redirect

DAG MBX CAS HUBUM Protocols; API; BizLogic Auth; Proxy; Redirect DAG MBX HUB* UM Protocols; API; BizLogic Auth; Proxy; Redirect Prot* MBX Server CAS

DAG MBX HUB Internet Site Boundary

DAG MBX HUB Internet Site Boundary

DAG MBX HUB Internet Site Boundary

DAG MBX HUB Internet Site Boundary

DAG MBX HUB Internet Site Boundary

DAG MBX HUB Internet Site Boundary

DAG MBX HUB DAG Transport CAS Internet Transport MBX CAS Frontend Site Boundary Mailbox Transport

DAG MBX HUB DAG Transport CAS Internet Transport MBX CAS Frontend Site Boundary Mailbox Transport

DAG MBX HUB DAG Transport CAS Internet Transport MBX CAS Frontend Site Boundary Mailbox Transport

DAG MBX HUB DAG Transport CAS Internet Transport MBX CAS Frontend Site Boundary Mailbox Transport

DAG MBX HUB DAG Transport CAS Internet Transport MBX CAS Frontend Site Boundary Mailbox Transport

DAG MBX HUB DAG Transport CAS Internet Transport MBX CAS Frontend Site Boundary Mailbox Transport

DAG MBX HUB DAG Transport CAS Internet Transport MBX CAS Frontend Site Boundary Mailbox Transport

DAG HUB Internet MBX Sub

DAG HUB Internet MBX Sub

DAG HUB Internet MBX Sub

DAG Transport CAS Internet Transport MBX CAS Frontend Mailbox Transport DAG HUB Internet MBX Sub

DAG Transport CAS Internet Transport MBX CAS Frontend Mailbox Transport DAG HUB Internet MBX Sub

DAG Transport CAS Internet Transport MBX CAS Frontend Mailbox Transport DAG HUB Internet MBX Sub

DAG Transport CAS Internet Transport MBX CAS Frontend Mailbox Transport DAG HUB Internet MBX Sub

AD Web browser Outlook (remote user) Mobile phone Outlook (local user) External SMTP servers Exchange Online Protection Enterprise Network 2 Building Blocks Client Access Server (CAS) Role Evolution of E2010 CAS Array Now includes SMTP Frontend Transport Primary function is to get the client to the right MBX server Mailbox Server Role Now includes all core messaging protocols Now includes Transport and Mailbox Transport (Delivery & Submission) Layer 4LB CAS Array CAS DAG2 MBX DAG3 MBX DAG1 MBX Frontend Transport Mailbox Transport Transport

AD Web browser Outlook (remote user) Mobile phone Outlook (local user) External SMTP servers Exchange Online Protection Enterprise Network 1. enters the organization Layer 4LB CAS Array CAS DAG2 DAG3 DAG1 1

AD Web browser Outlook (remote user) Mobile phone Outlook (local user) External SMTP servers Exchange Online Protection Enterprise Network Layer 4LB CAS Array CAS DAG2 DAG3 DAG enters the organization 2. Frontend Transport running on CAS server accepts the mail 1

AD Web browser Outlook (remote user) Mobile phone Outlook (local user) External SMTP servers Exchange Online Protection Enterprise Network Layer 4LB CAS Array CAS DAG2 DAG3 DAG enters the organization 2. Frontend Transport running on CAS server accepts the mail 3. Frontend Transport determines DAG for this recipient 1

AD Web browser Outlook (remote user) Mobile phone Outlook (local user) External SMTP servers Exchange Online Protection Enterprise Network Layer 4LB CAS Array CAS DAG2 DAG3 DAG1 1. enters the organization 2. Frontend Transport running on CAS server accepts the mail 3. Frontend Transport determines DAG for this recipient 4. CAS sends mail to a MBX server in the recipients DAG [prefers MBX server in its own site] MBX 4

AD Web browser Outlook (remote user) Mobile phone Outlook (local user) External SMTP servers Exchange Online Protection Enterprise Network Layer 4LB CAS Array CAS DAG2 MBX DAG3 MBX DAG1 MBX Frontend Transport 2 Building Blocks Client Access Server (CAS) Role Evolution of E2010 CAS Array Now includes SMTP Frontend Transport Primary function is to get the client to the right MBX server Mailbox Server Role Now includes all core messaging protocols Now includes Transport and Mailbox Transport (Delivery & Submission)

Handles inbound and outbound external SMTP traffic (Does not replace the Edge Transport Server Role) Handles authenticated client submissions Functions as a layer 7 proxy and has full access to protocol conversation (inbound) Will not queue or bifurcate mail locally All outbound traffic to next hop appears to come from the CAS2013 Listens on TCP25 and TCP587 and TCP717 Frontend Transport SMTP Receive Protocol Agents SMTP from MBX 2013 Authenticated SMTP SMTP Send SMTP to MBX 2013 External SMTP Mailbox Selector MSExchangeFrontendTransport.exe Anonymous SMTP

AD Web browser Outlook (remote user) Mobile phone Outlook (local user) External SMTP servers Exchange Online Protection Enterprise Network Layer 4LB CAS Array CAS DAG2 MBX DAG3 MBX DAG1 MBX Transport *previously known as Hub Transport 2 Building Blocks Client Access Server (CAS) Role Evolution of E2010 CAS Array Now includes SMTP Frontend Transport Primary function is to get the client to the right MBX server Mailbox Server Role Now includes all core messaging protocols Now includes Transport and Mailbox Transport (Delivery & Submission)

Processes all SMTP mail flow for the organization Will queue and route messages in and out of the organization Performs content inspection Supports extensibility in SMTP and categorizer Listens on TCP 25 (or TCP2525 when co-located with CAS) *previously known as Hub Transport Transport SMTP to MBX-Transport Delivery SMTP from MBX-Transport Submission SMTP from CAS SMTP to CAS, MBX, HUB Delivery Agents *other protocols Delivery Queue Pickup/Replay Categorizer Routing Agents SMTP Send SMTP Receive Protocol Agents Edgetransport.exe Mail.que Submission Queue

Categorizer Resolve Recipients SMTP Send SMTP Receive Protocol Agents Mail.que Submission Queue Find Route for Recipient Content Conversion & Bifurcation On SubmittedOn Resolved On Routed On Categorized External Delivery Queue Internal Delivery Queue Mailbox Delivery Queue

AD Web browser Outlook (remote user) Mobile phone Outlook (local user) External SMTP servers Exchange Online Protection Enterprise Network Layer 4LB CAS Array CAS DAG2 MBX DAG3 MBX DAG1 MBX Mailbox Transport Mailbox Transport Mailbox Transport 2 Building Blocks Client Access Server (CAS) Role Evolution of E2010 CAS Array Now includes SMTP Frontend Transport Primary function is to get the client to the right MBX server Mailbox Server Role Now includes all core messaging protocols Now includes Transport and Mailbox Transport (Delivery & Submission)

Handles mail submission and delivery from/to Store using two separate processes Does not have persistent storage Performs MIME to MAPI conversion (and vice versa) Combines Mailbox Assistant and Store Driver functionality (Supports all E2010 store driver extensibility events) Leverages local RPC for delivery to and submission from Store Does not support any extensibility SMTP from Transport Mailbox Transport SMTP Send SMTP Receive Submission Mailbox Assistants MAPI Store SMTP to Transport Submit Agents MSExchangeDelivery.exeMSExchangeSubmission.exe SMTP Send Deliver Agents Delivery SMTP to Transport

AD Web browser Outlook (remote user) Mobile phone Outlook (local user) External SMTP servers Exchange Online Protection Enterprise Network Layer 4LB CAS Array CAS DAG2 MBX DAG3 MBX DAG1 MBX

Edge Transport 2013 Ships in SP1 Used in perimeter network (non-domain joined) to accept mail Same feature set as Edge role in 2010 New monitoring framework (like rest of Exchange 2013) No AV; basic Anti- spam features; No Shadow copy Client submission still works via CAS AD Web browser Outlook (remote user) Mobile phone Outlook (local user) External SMTP servers Exchange Online Protection Enterprise Network DAG2 MBX DAG3 MBX DAG1 MBX Edge Transport Layer 4LB CAS Array CAS

Scenario 1 – Incoming mail on a multi-role server Scenario 2 – Incoming mail to two recipients Scenario 3 – Originating mail to Internet Scenario 4 – Originating mail to multiple recipients

DAG Internet Server Frontend Transport receives message on port looks up where recipient’s mailbox exists and routes to a Transport service within the DAG for that mailbox Transport receives message on port 2525 … processes it and routes it to mailbox transport delivery on server where mailbox is active Mailbox Transport Delivery receives the message on port 475 … converts MIME to MAPI and delivers message to Store. CAS 2013 Frontend Transport MBX 2013 Store Transport Mailbox Transport

Internet Frontend Transport EHLO 250OK MAIL FROM 250OK RCPT TO 250OK DATA

Internet Frontend Transport EHLO 250OK MAIL FROM 250OK RCPT TO 250OK DATA (TLS Session) EHLO XPROXYFROM MAIL FROM 250OK RCPT TO 250OK DATA 250OK (EXCHANGEAUTH) 250OK 250OK

Internet Frontend Transport EHLO 250OK MAIL FROM 250OK RCPT TO 250OK DATA (TLS Session) EHLO XPROXYFROM MAIL FROM 250OK RCPT TO 250OK DATA 250OK (EXCHANGEAUTH) 250OK 250OK 250OK QUIT

Internet Frontend Transport EHLO 250OK MAIL FROM 250OK RCPT TO 250OK DATA (TLS Session) EHLO XPROXYFROM MAIL FROM 250OK RCPT TO 250OK DATA 250OK (EXCHANGEAUTH) 250OK 250OK 250OK QUIT

Transport Mailbox Transport (TLS Session) EHLO MAIL FROM 250OK RCPT TO 250OK DATA 250OK QUIT XSESSIONSPARAMS (EXCHANGEAUTH) 250OK 250OK

Internet Frontend Transport EHLO 250OK MAIL FROM 250OK RCPT TO 250OK DATA (TLS Session) EHLO XPROXYFROM MAIL FROM 250OK RCPT TO 250OK DATA 250OK (EXCHANGEAUTH) 250OK 250OK 250OK QUIT Mailbox Transport (TLS Session) EHLO MAIL FROM 250OK RCPT TO 250OK DATA 250OK QUIT XSESSIONSPARAMS (EXCHANGEAUTH) 250OK 250OK

Received: from EXHV-1889.EXHV-5245dom.extest.microsoft.com (2001:4898:e8:3050:d9f3:8ace:7a2f:900b) by EXHV-1889.EXHV-5245dom.extest.microsoft.com (2001:4898:e8:3050:d9f3:8ace:7a2f:900b) with Microsoft SMTP Server (TLS) id via Mailbox Transport; Sun, 27 Jan :50: Received: from EXHV-1889.EXHV-5245dom.extest.microsoft.com (2001:4898:e8:3050:d9f3:8ace:7a2f:900b) by EXHV-1889.EXHV-5245dom.extest.microsoft.com (2001:4898:e8:3050:d9f3:8ace:7a2f:900b) with Microsoft SMTP Server (TLS) id ; Sun, 27 Jan :50: Received: from Internet ( ) by EXHV-1889.EXHV-5245dom.extest.microsoft.com ( ) with Microsoft SMTP Server (TLS) id via Frontend Transport; Sun, 27 Jan :50: Subject: Incoming mail on all-in-one role Message-ID: From:

DAG Internet CAS 2013 Frontend Transport MBX 2013 Store Transport Mailbox Transport Site CAS 2013 Frontend Transport MBX 2013 Store Transport Mailbox Transport 2 Recipients Site Boundary

Internet DAG CAS 2013 Frontend Transport MBX 2013 Store Transport Mailbox Transport Site CAS 2013 Frontend Transport MBX 2013 Store Transport Mailbox Transport

EHLO 250OK MAIL FROM 250OK RCPT TO 250OK DATA 250OK (TLS Session) QUIT Transport Mailbox Transport (EXCHANGEAUTH)

250OK (TLS Session) EHLO 250OK MAIL FROM 250OK RCPT TO 250OK DATA 250OK QUIT XPROXYTO MAIL FROM 250OK RCPT TO 250OK DATA 250OK Internet Frontend Transport

250OK (TLS Session) EHLO 250OK MAIL FROM 250OK RCPT TO 250OK DATA 250OK QUIT XPROXYTO MAIL FROM 250OK RCPT TO 250OK DATA 250OK Internet Frontend Transport Mailbox Transport EHLO 250OK MAIL FROM 250OK RCPT TO 250OK DATA 250OK (TLS Session) QUIT (EXCHANGEAUTH)

Internet DAG 2 CAS 2013 Frontend Transport MBX 2013 Transport Store Mailbox Transport DAG 1 CAS 2013 Frontend Transport MBX 2013 Store Transport Mailbox Transport Site CAS 2013 Frontend Transport MBX 2013 Store Transport Mailbox Transport 3 Recipients Site Boundary

Shadow is done ONLY by the Transport service Every message is redundantly persisted (shadowed) before its receipt is acknowledged to the sender If shadow can’t be made, Transport service will reject sender with response Transport service will first attempt to shadow to an active server in another site (but in the same DAG); after which will try to shadow to any active server in DAG Shadow server will periodically check with the primary server for a heartbeat; if no heartbeat for 3 hours, it will send message on behalf of primary Duplicate delivery detection present in store; in case primary resends message

DAG Internet CAS 2013 Frontend Transport MBX 2013 Store Transport Mailbox Transport Site CAS 2013 Frontend Transport MBX 2013 Store Transport Mailbox Transport SMTP Site Boundary

Internet Frontend Transport EHLO 250OK MAIL FROM 250OK RCPT TO 250OK DATA (TLS Session) EHLO XPROXYFROM MAIL FROM 250OK RCPT TO 250OK DATA 250OK (EXCHANGEAUTH) 250OK 250OK 250OK QUIT

Internet Frontend Transport EHLO 250OK MAIL FROM 250OK RCPT TO 250OK DATA (TLS Session) EHLO XPROXYFROM MAIL FROM 250OK RCPT TO 250OK DATA (EXCHANGEAUTH) 250OK 250OK Transport (MBX Svr1)

Internet Frontend Transport EHLO 250OK MAIL FROM 250OK RCPT TO 250OK DATA (TLS Session) EHLO XPROXYFROM MAIL FROM 250OK RCPT TO 250OK DATA (EXCHANGEAUTH) 250OK 250OK Transport (MBX Svr1) Transport (MBX Svr2) (TLS Session) EHLO MAIL FROM 250OK RCPT TO 250OK DATA (EXCHANGEAUTH) XSHADOWREQUEST 250OK QUIT

Internet Frontend Transport EHLO 250OK MAIL FROM 250OK RCPT TO 250OK DATA (TLS Session) EHLO XPROXYFROM MAIL FROM 250OK RCPT TO 250OK DATA (EXCHANGEAUTH) 250OK 250OK Transport (MBX Svr1) Transport (MBX Svr2) (TLS Session) EHLO MAIL FROM 250OK RCPT TO 250OK DATA (EXCHANGEAUTH) XSHADOWREQUEST 250OK QUIT 250OK 250OK QUIT

Transport (MBX Svr1) Transport (MBX Svr2) (TLS Session) EHLO (EXCHANGEAUTH) XSHADOW QUIT XQDISCARD 250 OK (MSG ID) 250 OK (TLS Session) EHLO (EXCHANGEAUTH) XSHADOW QUIT XQDISCARD 250 OK (MSG ID) 250 OK

DAG2 DAG1 CAS 2013 Frontend Transport M1 M2 M3 M4 DAG1 CAS 2013 Frontend Transport M5 Site 2 M6 M7 M8 mail.fabrikam.com Site 1 Site Boundary

Frontend Transport Mailbox Transport