February 2024
Beginner to intermediate
304 pages
9h 13m
Japanese
Content preview from 実務で使える メール技術の教科書 基本のしくみからプロトコル・サーバー構築・送信ドメイン認証・添付ファイル・暗号化・セキュリティ対策まで
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
3
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5
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メールの容量制限、再送、輻輳
■ 容量制限が必要な理由
多くのプロバイダや Web メールサービスでは、契約時にメールアドレスを
割り当てられますが、1 通あたりのメールサイズや、メールボックスに保存で
きる容量として上限が設けられています。
1 通あたりのメールの容量としては、5MB から 30MB 程度、メールボッ
クスの容量としては 1GB から 15GB 程度が多い傾向です。たとえば、無料
版の Gmail では、執筆時点で 1 通あたりの容量が 25MB、メールボックスの
上限が 15GB に設定されています。
このような上限が設定されている理由として、大容量のメールを送受信され
ると、メールサーバーのストレージ容量やネットワーク帯域幅に影響を与える
ことが挙げられます。そのサーバーの利用者が 1 人であれば問題なくても、
メールサーバーは複数の利用者が共同で利用するため、特定の利用者が大容量
のメールをやり取りすると、他の利用者に影響が出る可能性があるためです
【図 3-9】。
3
5
メールの容量制限、再送、輻輳
・大容量のメールの送信が制限される理由を知りたい人
・送信時に制限をかけるため、SMTP サーバーで設定するとき
・メールボックスのサイズで受信側に制限をかけるとき
・メールの一時的な配信失敗に対する再送のしくみを知りたいとき
使えるのはこんな人や場面！
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.