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    Email Send Error Research

    Water Closet
    smtp email imap
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    • WrCombsW
      WrCombs @scottalanmiller
      last edited by

      @scottalanmiller said in Email Send error;:

      @wrcombs said in Email Send error;:

      So I told him to reach out to his Email Admin and have them make the required changes in outlook..

      Outlook is a desktop client. Seems unlikely their email admin would have access. Their desktop admin would normally do it.

      this is the same person at this location. . .

      JaredBuschJ 1 Reply Last reply Reply Quote 0
      • JaredBuschJ
        JaredBusch @WrCombs
        last edited by

        @wrcombs said in Email Send error;:

        @scottalanmiller said in Email Send error;:

        @wrcombs said in Email Send error;:

        So I told him to reach out to his Email Admin and have them make the required changes in outlook..

        Outlook is a desktop client. Seems unlikely their email admin would have access. Their desktop admin would normally do it.

        this is the same person at this location. . .

        @scottalanmiller is being a @scottalanmiller ...

        The rest of us understand that.

        The rest of us also understand that you are not talking about the email server for sending and receiving and we are not trying to confuse you by bringing in more information than you can understand.

        1 Reply Last reply Reply Quote 0
        • 1
          1337 @WrCombs
          last edited by 1337

          @wrcombs said in Email Send error;:

          @scottalanmiller said in Email Send error;:

          @wrcombs said in Email Send error;:

          @pete-s said in Email Send error;:

          @wrcombs said in Email Send error;:

          @pete-s said in Email Send error;:

          @wrcombs said in Email Send error;:

          @jaredbusch said in Email Send error;:

          @wrcombs said in Email Send error;:

          I couldn't find any of the settings, using the latest version of outlook..

          What is the email server? Gmail? Outlook.com? O365? GSuite? ZoHo? You have to know this.

          I don't have that information.. and I have no way of finding that out..

          Well shit.

          If you ever received an email from this person, you already have that information.

          is that right?

          can you explain what you mean, please ?

          Take the email you received and look for "Show Original" or something similar in your mail client.

          It will show all the headers and information that the mail servers have sent between them. There you can see what provider someone is using. Often also what mail client.

          this?

          spf=pass (google.com: domain

          Don't trim it out.

          I dont know what I'm looking for, Google wasn't much help but i'll figure it out

          You're not just looking for one string. You need to look at the whole thing.

          I suggest you copy the headers from the start until you reach the line starting with From:
          Paste it into this page: https://mxtoolbox.com/EmailHeaders.aspx

          It should tell you what servers are in use for sending and receiving.

          WrCombsW 1 Reply Last reply Reply Quote 2
          • WrCombsW
            WrCombs @1337
            last edited by

            @pete-s said in Email Send error;:

            @wrcombs said in Email Send error;:

            @scottalanmiller said in Email Send error;:

            @wrcombs said in Email Send error;:

            @pete-s said in Email Send error;:

            @wrcombs said in Email Send error;:

            @pete-s said in Email Send error;:

            @wrcombs said in Email Send error;:

            @jaredbusch said in Email Send error;:

            @wrcombs said in Email Send error;:

            I couldn't find any of the settings, using the latest version of outlook..

            What is the email server? Gmail? Outlook.com? O365? GSuite? ZoHo? You have to know this.

            I don't have that information.. and I have no way of finding that out..

            Well shit.

            If you ever received an email from this person, you already have that information.

            is that right?

            can you explain what you mean, please ?

            Take the email you received and look for "Show Original" or something similar in your mail client.

            It will show all the headers and information that the mail servers have sent between them. There you can see what provider someone is using. Often also what mail client.

            this?

            spf=pass (google.com: domain

            Don't trim it out.

            I dont know what I'm looking for, Google wasn't much help but i'll figure it out

            You're not just looking for one string. You need to look at the whole thing.

            I suggest you copy the headers from the start until you reach the line starting with From:
            Paste it into this page: https://mxtoolbox.com/EmailHeaders.aspx

            It should tell you what servers are in use for sending and receiving.

            So I did that this morning - and I'm not sure what I'm looking at.

            1 Reply Last reply Reply Quote 0
            • J
              JasGot @WrCombs
              last edited by

              @wrcombs said in Email Send error;:

              0x800CCC7D

              What version of Windows and What version of Outlook?

              WrCombsW 1 Reply Last reply Reply Quote 0
              • WrCombsW
                WrCombs @JasGot
                last edited by WrCombs

                @jasgot said in Email Send error;:

                @wrcombs said in Email Send error;:

                0x800CCC7D

                What version of Windows and What version of Outlook?

                Windows 10

                I didn't look - we dont support email so this is mostly just a way of wondering what I should be looking for in the future.

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

                  @wrcombs Post the entire header - look it over for any private information and XXXX that out...

                  WrCombsW 1 Reply Last reply Reply Quote 0
                  • WrCombsW
                    WrCombs @Dashrender
                    last edited by

                    @dashrender said in Email Send error;:

                    @wrcombs Post the entire header - look it over for any private information and XXXX that out...

                    Delivered-To: XXXXXXXXXXXXXX
                    Received: by 2002:a05:6830:319b:0:0:0:0 with SMTP id p27csp165790ots;
                            Wed, 9 Jun 2021 15:47:06 -0700 (PDT)
                    X-Google-Smtp-Source: ABdhPJw/sNc2TPrI5ipWcQK3cbAFhs19oUYuPX9foV/mFqOqPBAovXmKBs8xjw+zyJKjNNxI728X
                    X-Received: by 2002:a4a:be86:: with SMTP id o6mr1857338oop.67.1623278826653;
                            Wed, 09 Jun 2021 15:47:06 -0700 (PDT)
                    ARC-Seal: i=1; a=rsa-sha256; t=1623278826; cv=none;
                            d=google.com; s=arc-20160816;
                            b=M8FFBcGifjCQFjstZhbk3RHRufue28cmQwTteQnN5nKpLXEHJX+899bBzhT0CTiDX4
                             /+MUfqy0oF30khO2+3J8lwWrqT2iUzi6oAUegn33oGdAaSUMFy13OYW/uosrBr3aNUxB
                             1T+Z8x6iNHF6Wr1KGJy7Xdfw0NJPjjoPy7cZA+CD/1cMaSw0vr3vw308sf9UoQdXrIO6
                             a0EGWHEddgIE/vLnWqdnhoEqEnumALd9g/J47OjI7GTQo5R4bG1Du7eNTERX/8nh+3Nl
                             iVAetsU7PrfLKFkIrSpWasTEBxSsd/l9uYMfULWgy2cHL0qlXBe98TEXxDk9+GLCYw88
                             qWNw==
                    ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816;
                            h=to:references:message-id:in-reply-to:thread-topic:subject:from:date
                             :mime-version:dkim-signature;
                            bh=359hOSgFVIyouoKXJjcrY15MgMQrI1lSw8u4akJ8Hgg=;
                            b=dJv8SkgV1XvraGCosxXttUPoDwpWeSJ/ufjQ3nEmf8zf7pogH6SfiXH2I8vvPfOSQ+
                             qxH3w1mOm2X+nlShqNpbSDy1vVzYDQwV2CrrWVdnuzKvhC1wSJxS1LojmQev71SMTylJ
                             7ELX6N5CsnF7mXrid3d/xk1d4xrJnZGvJ+F9o6SpqLCOrxu34fPVEdnC09k0ETXThL/N
                             ++46c9/3AxrYHahUlaILoXJ2mD2EIBSZe34wI5ScoD91y59TnE6EpOfDmfz+nECQP2G2
                             v0AJCazoKXVEIds95f9r0WyiEsS8rSNmIxiAcAY6Vf6MUb9vNR3B32eK2vxC8buBobCm
                             HVLQ==
                    ARC-Authentication-Results: i=1; mx.google.com;
                           dkim=pass [email protected] header.s=modoboa header.b=a9kvuLKl;
                           spf=pass (google.com: domain of XXXXXXXXX designates XXX.XXX.XXX.XXX as permitted sender) smtp.mailfrom=XXXXXXXXXXXXXX;
                           dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=XXXXXXXX
                    Return-Path: <XXXXXXXXXX>
                    Received: fromXXXX.XXXXXX.com (XXXXXXXXXX [XXX.XXX.XXX.XXX])
                            by mx.google.com with ESMTPS id h18si1327216otk.177.2021.06.09.15.47.06
                            (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
                            Wed, 09 Jun 2021 15:47:06 -0700 (PDT)
                    Received-SPF: pass (google.com: domain of XXXXXXXXXX designates XXX.XXX.XXX.XXX as permitted sender) client-ip=XXX.XXX.XXX.XXX;
                    Authentication-Results: mx.google.com;
                           dkim=pass [email protected] header.s=modoboa header.b=a9kvuLKl;
                           spf=pass (google.com: domain of XXXXXXXXXX.com designates XXX.XXX.XXX.XXX as permitted sender) smtp.mailfrom=XXXXXXXXX.com;
                           dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=XXXXXX.com
                    Received: from localhost XXX-XX-XXX-XXXX.mobile.uscc.net [XXX.XXX.XXX.XXX]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) by XXXX.XXXXXX.com (Postfix) with ESMTPSA id 80B013EC2E; Wed,
                      9 Jun 2021 22:47:05 +0000 (UTC)
                    DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=prlwm.com; s=modoboa; t=1623278826; bh=359hOSgFVIyouoKXJjcrY15MgMQrI1lSw8u4akJ8Hgg=; h=Date:From:Subject:In-Reply-To:References:To:From; b=a9kvuLKlssqgoFBtbdLpAmaqAryNVeCxp3U8ZK3ghO/IgPrgc8hZqZOdtV4MRXDoO
                    	 rr46IQn8KpdI9AADOrRWCtMHys2bzlG3sHsUxGzyivm89BhCNVji4HElpxkApGbRe3
                    	 /Y/+XXHAtIJwMHCtnEJtKIjzZQglj5Y+3a2wnmzVtqp4mfeMLageTggGXnmVxnOtyo
                    	 NMFGnYJPOXQ5q9iprRGgLDpdXpdz1AaAT8eai+Gzoj1iH9KLKSmDTtuDpJJsHEya8W
                    	 6HwgZrDUndamHVnju6xXdJly2sNHjp+jtH7Dm779w+HESzsRc5n6n5nYpikW8rdeHq
                    	 4FPbve1Zz6waw==
                    MIME-Version: 1.0
                    Date: Wed, 9 Jun 2021 17:47:04 -0500
                    From: XXXXXXXXXXXXXXXX
                    Subject: Re: XXXXXXXXXXXXXXXX
                    Thread-Topic: Re: XXXXXXXXXXXXX
                    In-Reply-To: <CANZe-Sm6+Ois=T+b+UgCMfXg9xaOLKqyp=dKt=OQR279ynVB4A@mail.gmail.com>
                    Message-ID: <[email protected]>
                    References: <DM6PR15MB4089CE7329169D4C0A2834B4BE379@DM6PR15MB4089.namprd15.prod.outlook.com> <CANZe-Sk_T77wtN5vhe6j2TMKNFYpdEpEDNHN-OSEEWMYo3a+qg@mail.gmail.com> <DM6PR15MB4089DFBF7550A4FA6032E634BE369@DM6PR15MB4089.namprd15.prod.outlook.com>,<CANZe-
                    1 JaredBuschJ 2 Replies Last reply Reply Quote 0
                    • 1
                      1337 @WrCombs
                      last edited by 1337

                      @wrcombs said in Email Send error;:

                      @dashrender said in Email Send error;:

                      @wrcombs Post the entire header - look it over for any private information and XXXX that out...

                      You have three Received: sections.

                      The bottom one is the first one that happened. That's the sender connecting to something. You can see the ISP he's using, his local IP usually and what SMTP server he connects to.

                      Received: from localhost XXX-XX-XXX-XXXX.mobile.uscc.net [XXX.XXX.XXX.XXX]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) by XXXX.XXXXXX.com (Postfix) with ESMTPSA id 80B013EC2E; Wed,
                        9 Jun 2021 22:47:05 +0000 (UTC)
                      

                      The middle one is the next. The mail is now sent from something to mx.google.com. That's a google mail server.

                      Received: fromXXXX.XXXXXX.com (XXXXXXXXXX [XXX.XXX.XXX.XXX])
                              by mx.google.com with ESMTPS id h18si1327216otk.177.2021.06.09.15.47.06
                              (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
                              Wed, 09 Jun 2021 15:47:06 -0700 (PDT)
                      

                      The top one is the last transfer. There's missing "from" but judging from the IPv6 address this is likely internal google mail server to google mail server.

                      Received: by 2002:a05:6830:319b:0:0:0:0 with SMTP id p27csp165790ots;
                              Wed, 9 Jun 2021 15:47:06 -0700 (PDT)
                      

                      You can also get information from the Received-SPF: section.

                      Received-SPF: pass (google.com: domain of XXXXXXXXXX designates XXX.XXX.XXX.XXX as permitted sender) client-ip=XXX.XXX.XXX.XXX;
                      

                      It's google mail server telling you that the domain XXXXXXXXXX says that XXX.XXX.XXX.XXX is allowed to send emails.

                      WrCombsW 1 Reply Last reply Reply Quote 1
                      • WrCombsW
                        WrCombs @1337
                        last edited by

                        @pete-s said in Email Send Error Research:

                        @wrcombs said in Email Send error;:

                        @dashrender said in Email Send error;:

                        @wrcombs Post the entire header - look it over for any private information and XXXX that out...

                        You have three Received: sections.

                        The bottom one is the first one that happened. That's the sender connecting to something. You can see the ISP he's using, his local IP usually and what SMTP server he connects to.

                        Received: from localhost XXX-XX-XXX-XXXX.mobile.uscc.net [XXX.XXX.XXX.XXX]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) by XXXX.XXXXXX.com (Postfix) with ESMTPSA id 80B013EC2E; Wed,
                          9 Jun 2021 22:47:05 +0000 (UTC)
                        

                        The middle one is the next. The mail is now sent from something to mx.google.com. That's a google mail server.

                        Received: fromXXXX.XXXXXX.com (XXXXXXXXXX [XXX.XXX.XXX.XXX])
                                by mx.google.com with ESMTPS id h18si1327216otk.177.2021.06.09.15.47.06
                                (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
                                Wed, 09 Jun 2021 15:47:06 -0700 (PDT)
                        

                        The top one is the last transfer. There's missing "from" but judging from the IPv6 address this is likely internal google mail server to google mail server.

                        Received: by 2002:a05:6830:319b:0:0:0:0 with SMTP id p27csp165790ots;
                                Wed, 9 Jun 2021 15:47:06 -0700 (PDT)
                        

                        You can also get information from the Received-SPF: section.

                        Received-SPF: pass (google.com: domain of XXXXXXXXXX designates XXX.XXX.XXX.XXX as permitted sender) client-ip=XXX.XXX.XXX.XXX;
                        

                        It's google mail server telling you that the domain XXXXXXXXXX says that XXX.XXX.XXX.XXX is allowed to send emails.

                        But it doesn't tell me which Email server they're using on Outlook.. I thought that was the question

                        1 1 Reply Last reply Reply Quote 0
                        • 1
                          1337 @WrCombs
                          last edited by

                          @wrcombs said in Email Send Error Research:

                          @pete-s said in Email Send Error Research:

                          @wrcombs said in Email Send error;:

                          @dashrender said in Email Send error;:

                          @wrcombs Post the entire header - look it over for any private information and XXXX that out...

                          You have three Received: sections.

                          The bottom one is the first one that happened. That's the sender connecting to something. You can see the ISP he's using, his local IP usually and what SMTP server he connects to.

                          Received: from localhost XXX-XX-XXX-XXXX.mobile.uscc.net [XXX.XXX.XXX.XXX]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) by XXXX.XXXXXX.com (Postfix) with ESMTPSA id 80B013EC2E; Wed,
                            9 Jun 2021 22:47:05 +0000 (UTC)
                          

                          The middle one is the next. The mail is now sent from something to mx.google.com. That's a google mail server.

                          Received: fromXXXX.XXXXXX.com (XXXXXXXXXX [XXX.XXX.XXX.XXX])
                                  by mx.google.com with ESMTPS id h18si1327216otk.177.2021.06.09.15.47.06
                                  (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
                                  Wed, 09 Jun 2021 15:47:06 -0700 (PDT)
                          

                          The top one is the last transfer. There's missing "from" but judging from the IPv6 address this is likely internal google mail server to google mail server.

                          Received: by 2002:a05:6830:319b:0:0:0:0 with SMTP id p27csp165790ots;
                                  Wed, 9 Jun 2021 15:47:06 -0700 (PDT)
                          

                          You can also get information from the Received-SPF: section.

                          Received-SPF: pass (google.com: domain of XXXXXXXXXX designates XXX.XXX.XXX.XXX as permitted sender) client-ip=XXX.XXX.XXX.XXX;
                          

                          It's google mail server telling you that the domain XXXXXXXXXX says that XXX.XXX.XXX.XXX is allowed to send emails.

                          But it doesn't tell me which Email server they're using on Outlook.. I thought that was the question

                          Yes, it does:

                           Received: from localhost XXX-XX-XXX-XXXX.mobile.uscc.net [XXX.XXX.XXX.XXX]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) by XXXX.XXXXXX.com (Postfix) with ESMTPSA id 80B013EC2E; Wed,
                             9 Jun 2021 22:47:05 +0000 (UTC)
                          

                          by XXXX.XXXXXX.com (Postfix)

                          That's the SMTP server they connect to. It's running Postfix software.
                          They have mobile.uscc.net as ISP.

                          WrCombsW 1 Reply Last reply Reply Quote 1
                          • WrCombsW
                            WrCombs @1337
                            last edited by

                            @pete-s said in Email Send Error Research:

                            @wrcombs said in Email Send Error Research:

                            @pete-s said in Email Send Error Research:

                            @wrcombs said in Email Send error;:

                            @dashrender said in Email Send error;:

                            @wrcombs Post the entire header - look it over for any private information and XXXX that out...

                            You have three Received: sections.

                            The bottom one is the first one that happened. That's the sender connecting to something. You can see the ISP he's using, his local IP usually and what SMTP server he connects to.

                            Received: from localhost XXX-XX-XXX-XXXX.mobile.uscc.net [XXX.XXX.XXX.XXX]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) by XXXX.XXXXXX.com (Postfix) with ESMTPSA id 80B013EC2E; Wed,
                              9 Jun 2021 22:47:05 +0000 (UTC)
                            

                            The middle one is the next. The mail is now sent from something to mx.google.com. That's a google mail server.

                            Received: fromXXXX.XXXXXX.com (XXXXXXXXXX [XXX.XXX.XXX.XXX])
                                    by mx.google.com with ESMTPS id h18si1327216otk.177.2021.06.09.15.47.06
                                    (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
                                    Wed, 09 Jun 2021 15:47:06 -0700 (PDT)
                            

                            The top one is the last transfer. There's missing "from" but judging from the IPv6 address this is likely internal google mail server to google mail server.

                            Received: by 2002:a05:6830:319b:0:0:0:0 with SMTP id p27csp165790ots;
                                    Wed, 9 Jun 2021 15:47:06 -0700 (PDT)
                            

                            You can also get information from the Received-SPF: section.

                            Received-SPF: pass (google.com: domain of XXXXXXXXXX designates XXX.XXX.XXX.XXX as permitted sender) client-ip=XXX.XXX.XXX.XXX;
                            

                            It's google mail server telling you that the domain XXXXXXXXXX says that XXX.XXX.XXX.XXX is allowed to send emails.

                            But it doesn't tell me which Email server they're using on Outlook.. I thought that was the question

                            Yes, it does:

                             Received: from localhost XXX-XX-XXX-XXXX.mobile.uscc.net [XXX.XXX.XXX.XXX]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) by XXXX.XXXXXX.com (Postfix) with ESMTPSA id 80B013EC2E; Wed,
                               9 Jun 2021 22:47:05 +0000 (UTC)
                            

                            by XXXX.XXXXXX.com (Postfix)

                            That's the SMTP server they connect to. It's running Postfix software.
                            They have mobile.uscc.net as ISP.

                            Ah, missed that.

                            SO they're running Postfix as a mail server?

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

                              @wrcombs said in Email Send Error Research:

                              SO they're running Postfix as a mail server?

                              Yes, which most people do. Postfix powers the vast majority of non-Exchange email. It's the big leader.

                              WrCombsW JaredBuschJ 2 Replies Last reply Reply Quote 1
                              • WrCombsW
                                WrCombs @scottalanmiller
                                last edited by

                                @scottalanmiller said in Email Send Error Research:

                                @wrcombs said in Email Send Error Research:

                                SO they're running Postfix as a mail server?

                                Yes, which most people do. Postfix powers the vast majority of non-Exchange email. It's the big leader.

                                Okay great ..

                                @JaredBusch They're running Postfix mail Server on outlook.

                                JaredBuschJ scottalanmillerS 2 Replies Last reply Reply Quote 0
                                • JaredBuschJ
                                  JaredBusch @scottalanmiller
                                  last edited by

                                  @scottalanmiller said in Email Send Error Research:

                                  @wrcombs said in Email Send Error Research:

                                  SO they're running Postfix as a mail server?

                                  Yes, which most people do. Postfix powers the vast majority of non-Exchange email. It's the big leader.

                                  No, they are not. Their mail provider is running Postfix.

                                  Their provider is their ISP.

                                  1 Reply Last reply Reply Quote 0
                                  • JaredBuschJ
                                    JaredBusch @WrCombs
                                    last edited by JaredBusch

                                    @wrcombs said in Email Send Error Research:

                                    @scottalanmiller said in Email Send Error Research:

                                    @wrcombs said in Email Send Error Research:

                                    SO they're running Postfix as a mail server?

                                    Yes, which most people do. Postfix powers the vast majority of non-Exchange email. It's the big leader.

                                    Okay great ..

                                    @JaredBusch They're running Postfix mail Server on outlook.

                                    No. They user is running outlook.

                                    They are connecting to their ISP’s domain email server, likely "free email" with domain purchase bullshit, which is running postfix

                                    Outlook connects to this type of server with SMTP

                                    1 Reply Last reply Reply Quote 2
                                    • JaredBuschJ
                                      JaredBusch @WrCombs
                                      last edited by

                                      @wrcombs said in Email Send Error Research:

                                      Received: from localhost XXX-XX-XXX-XXXX.mobile.uscc.net [XXX.XXX.XXX.XXX]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) by XXXX.XXXXXX.com (Postfix) with ESMTPSA id 80B013EC2E; Wed, 9 Jun 2021 22:47:05 +0000 (UTC)
                                      

                                      Let's break this down. This is the one that concerns you.

                                      The mail hit the email system from this IP address
                                      Received: from localhost XXX-XX-XXX-XXXX.mobile.uscc.net [XXX.XXX.XXX.XXX])

                                      The email was TLS encrypted
                                      (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits))

                                      The mail was recevied by this server running postfix.
                                      by XXXX.XXXXXX.com (Postfix)

                                      We can assume that this is showing his domain since you redacted it.

                                      Because it is his domain, this is likely shit "free email" from a cpanel webhost.

                                      Finally, this tell us that he authenticates to send SMTP to his host.
                                      with ESMTPSA

                                      WrCombsW 1 Reply Last reply Reply Quote 1
                                      • WrCombsW
                                        WrCombs @JaredBusch
                                        last edited by

                                        @jaredbusch Good information to know.. Thank you.

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

                                          @wrcombs said in Email Send Error Research:

                                          @scottalanmiller said in Email Send Error Research:

                                          @wrcombs said in Email Send Error Research:

                                          SO they're running Postfix as a mail server?

                                          Yes, which most people do. Postfix powers the vast majority of non-Exchange email. It's the big leader.

                                          Okay great ..

                                          @JaredBusch They're running Postfix mail Server on outlook.

                                          Outlook is an email client. It runs on your desktop. It's not a server or anything like that. Nothing runs "on it."

                                          JaredBuschJ 1 Reply Last reply Reply Quote 0
                                          • JaredBuschJ
                                            JaredBusch
                                            last edited by JaredBusch

                                            Now that we know all of that, you can make some assumptions about the connection in Outlook.

                                            SMTP can use any port.
                                            Port 25 is the original, standard, unauthenticated port. But also blocked on most end user connections.

                                            Typcially CPanel hosts use the standardized port 587 for inbound TLS connections.

                                            So his Outlook is most likely configured to point to mail.domain.com:587 or simply domain.com:587 to send SMTP.

                                            Adding in authentication means it is sent with a username and password. Username is typically the full email address.

                                            WrCombsW 1 Reply Last reply Reply Quote 0
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