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    Solved Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.

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    • Mike DavisM
      Mike Davis
      last edited by

      The ports you're looking at are the ones typically used by imap. Office 365 does most everything over 443.

      On your firewall, you still want to block (and log if you can) any traffic on port 25 in case a machine on your LAN gets infected and tries to start spamming mail servers directly.

      scottalanmillerS openitO 2 Replies Last reply Reply Quote 0
      • scottalanmillerS
        scottalanmiller @Mike Davis
        last edited by

        @Mike-Davis said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

        The ports you're looking at are the ones typically used by imap. Office 365 does most everything over 443.

        Even when not using 443, Outlook to Exchange is not an IMAP connection so would never be involved there.

        1 Reply Last reply Reply Quote 1
        • openitO
          openit @Mike Davis
          last edited by

          @Mike-Davis said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

          The ports you're looking at are the ones typically used by imap. Office 365 does most everything over 443.

          On your firewall, you still want to block (and log if you can) any traffic on port 25 in case a machine on your LAN gets infected and tries to start spamming mail servers directly.

          Yup, we are blocking port 25 explicitly on firewall.

          1 Reply Last reply Reply Quote 0
          • DashrenderD
            Dashrender
            last edited by

            I would fully expect the emails to be in an encrypted tunnel from the Outlook client (or whatever email client you're using) to O365. Unless you're using some type of proxy that can be a MITM, I don't think anything will see those messages. Even then - Does Outlook get them as email messages?

            openitO 1 Reply Last reply Reply Quote 0
            • openitO
              openit @Dashrender
              last edited by

              @Dashrender said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

              I would fully expect the emails to be in an encrypted tunnel from the Outlook client (or whatever email client you're using) to O365. Unless you're using some type of proxy that can be a MITM, I don't think anything will see those messages. Even then - Does Outlook get them as email messages?

              Not sure.

              1 Reply Last reply Reply Quote 0
              • openitO
                openit
                last edited by

                Ok, I understand, due to direct connection from Outlook with exchange, no port is being hit on Firewall. So only non-genuine emails going to be recognized at firewall.

                Thanks.

                scottalanmillerS 1 Reply Last reply Reply Quote 0
                • scottalanmillerS
                  scottalanmiller @openit
                  last edited by

                  @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                  Ok, I understand, due to direct connection from Outlook with exchange, no port is being hit on Firewall. So only non-genuine emails going to be recognized at firewall.

                  Thanks.

                  Correct. Outlook has basically a private VPN back to the Exchange server over port 443 so no visible traffic of email on your network because there is none. That's better, so ANY SMTP traffic, on any port, is suspect.

                  openitO 1 Reply Last reply Reply Quote 3
                  • openitO
                    openit @scottalanmiller
                    last edited by

                    @scottalanmiller said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                    @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                    Ok, I understand, due to direct connection from Outlook with exchange, no port is being hit on Firewall. So only non-genuine emails going to be recognized at firewall.

                    Thanks.

                    Correct. Outlook has basically a private VPN back to the Exchange server over port 443 so no visible traffic of email on your network because there is none. That's better, so ANY SMTP traffic, on any port, is suspect.

                    Is that also means, if our ISP is blocking our email things due to Spam issue, it's not going to effect our O365 users (while they send emails through outlook client) ?

                    scottalanmillerS 1 Reply Last reply Reply Quote 0
                    • scottalanmillerS
                      scottalanmiller @openit
                      last edited by

                      @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                      @scottalanmiller said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                      @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                      Ok, I understand, due to direct connection from Outlook with exchange, no port is being hit on Firewall. So only non-genuine emails going to be recognized at firewall.

                      Thanks.

                      Correct. Outlook has basically a private VPN back to the Exchange server over port 443 so no visible traffic of email on your network because there is none. That's better, so ANY SMTP traffic, on any port, is suspect.

                      Is that also means, if our ISP is blocking our email things due to Spam issue, it's not going to effect our O365 users (while they send emails through outlook client) ?

                      Outlook doesn't use SMTP or send email, it sends instructions to Exchange, which is totally different. No email protocols are involved.

                      openitO 1 Reply Last reply Reply Quote 0
                      • openitO
                        openit @scottalanmiller
                        last edited by

                        @scottalanmiller said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                        @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                        @scottalanmiller said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                        @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                        Ok, I understand, due to direct connection from Outlook with exchange, no port is being hit on Firewall. So only non-genuine emails going to be recognized at firewall.

                        Thanks.

                        Correct. Outlook has basically a private VPN back to the Exchange server over port 443 so no visible traffic of email on your network because there is none. That's better, so ANY SMTP traffic, on any port, is suspect.

                        Is that also means, if our ISP is blocking our email things due to Spam issue, it's not going to effect our O365 users (while they send emails through outlook client) ?

                        Outlook doesn't use SMTP or send email, it sends instructions to Exchange, which is totally different. No email protocols are involved.

                        Okay, so any email ports blocked by our ISP is not going to effect our O365 users.

                        scottalanmillerS 1 Reply Last reply Reply Quote 0
                        • scottalanmillerS
                          scottalanmiller @openit
                          last edited by

                          @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                          @scottalanmiller said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                          @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                          @scottalanmiller said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                          @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                          Ok, I understand, due to direct connection from Outlook with exchange, no port is being hit on Firewall. So only non-genuine emails going to be recognized at firewall.

                          Thanks.

                          Correct. Outlook has basically a private VPN back to the Exchange server over port 443 so no visible traffic of email on your network because there is none. That's better, so ANY SMTP traffic, on any port, is suspect.

                          Is that also means, if our ISP is blocking our email things due to Spam issue, it's not going to effect our O365 users (while they send emails through outlook client) ?

                          Outlook doesn't use SMTP or send email, it sends instructions to Exchange, which is totally different. No email protocols are involved.

                          Okay, so any email ports blocked by our ISP is not going to effect our O365 users.

                          Correct. You are not sending email in and out of your network, you are only looking at the email system remotely. There are no email protocols, no email traffic and no actual email moving across your network with the tools that you are using.

                          JaredBuschJ 1 Reply Last reply Reply Quote 1
                          • JaredBuschJ
                            JaredBusch @scottalanmiller
                            last edited by

                            @scottalanmiller said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                            @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                            @scottalanmiller said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                            @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                            @scottalanmiller said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                            @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                            Ok, I understand, due to direct connection from Outlook with exchange, no port is being hit on Firewall. So only non-genuine emails going to be recognized at firewall.

                            Thanks.

                            Correct. Outlook has basically a private VPN back to the Exchange server over port 443 so no visible traffic of email on your network because there is none. That's better, so ANY SMTP traffic, on any port, is suspect.

                            Is that also means, if our ISP is blocking our email things due to Spam issue, it's not going to effect our O365 users (while they send emails through outlook client) ?

                            Outlook doesn't use SMTP or send email, it sends instructions to Exchange, which is totally different. No email protocols are involved.

                            Okay, so any email ports blocked by our ISP is not going to effect our O365 users.

                            Correct. You are not sending email in and out of your network, you are only looking at the email system remotely. There are no email protocols, no email traffic and no actual email moving across your network with the tools that you are using.

                            It has nothing to do with Office365 either. Outlook does not use email protocols for any thing on an exchange server. In house or otherwise.

                            scottalanmillerS 1 Reply Last reply Reply Quote 1
                            • scottalanmillerS
                              scottalanmiller @JaredBusch
                              last edited by

                              @JaredBusch said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                              @scottalanmiller said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                              @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                              @scottalanmiller said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                              @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                              @scottalanmiller said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                              @openit said in Not seeing traffic for O365 emails at 587, 993 and 995 ports on Firewall.:

                              Ok, I understand, due to direct connection from Outlook with exchange, no port is being hit on Firewall. So only non-genuine emails going to be recognized at firewall.

                              Thanks.

                              Correct. Outlook has basically a private VPN back to the Exchange server over port 443 so no visible traffic of email on your network because there is none. That's better, so ANY SMTP traffic, on any port, is suspect.

                              Is that also means, if our ISP is blocking our email things due to Spam issue, it's not going to effect our O365 users (while they send emails through outlook client) ?

                              Outlook doesn't use SMTP or send email, it sends instructions to Exchange, which is totally different. No email protocols are involved.

                              Okay, so any email ports blocked by our ISP is not going to effect our O365 users.

                              Correct. You are not sending email in and out of your network, you are only looking at the email system remotely. There are no email protocols, no email traffic and no actual email moving across your network with the tools that you are using.

                              It has nothing to do with Office365 either. Outlook does not use email protocols for any thing on an exchange server. In house or otherwise.

                              Right, good point. This is all just general Exchange / Outlook protocol info, not related to a specific hosting service.

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