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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Let's learn about email technology!
また、偽のメールサーバーに対応する DNS サーバーに DKIM を設定するこ
とも考えられます。DKIM の署名に記述されたドメイン名のサーバーから送信
すると、DKIM の署名やハッシュの検証にも成功します。これは SPF のとき
と同様に、ヘッダーの From を偽装することで、受信者は気づかない可能性
があります【図 5-12】。
■ DKIM のしくみ
DKIM による署名を実現するためには、SPF と同様に DNS サーバーを設
定します。具体的には、次のようなテキストレコードを DNS サーバーに登録
します。これを DKIM レコードといいます。
図 5-11
DKIM をつけずに送信する
DKIMを検証しないので、
一般的なメールと変わらない
【偽装した利用者】
DKIM
を使わずに送信
DNSサーバー
dkim＝pass
dkim＝none
【正規の利用者】
DKIM
で署名を付加して送信
図 5-12
偽の DKIM を付加して送信する
DNSサーバー
【偽装した利用者】
偽の
DKIMで署名を付加して送信
DNSサーバー
dkim＝pass
dkim＝pass
【正規の利用者】
DKIM
で署名を付加して送信
202
185-216̲mail̲NSM̲F2.indd202185-216̲mail̲NSM̲F2.indd202 2024/01/2510:062024/01/2510:06
5
−
2
—
—
送信者の認証による対策
この
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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.