We are reporting password brute-force attacks against our mail server from an IP address in your network. This may be a compromised customer server. Source IP: 5.104.87.243 Activity: SMTP submission (AUTH) password brute force (repeated login attempts with many usernames) Period (UTC): 2026-10-08 21:11 to 2026-10-13 09:39 Connections: 1,253 to TCP/587 (about 276 per day) Target: 210.143.107.113 None of the attempts succeeded, and we have blocked this source on our firewall. Detailed logs are available on request. Please investigate and stop this activity. Best regards, ============================== 株式会社デジタルライン 安原 英明 / Yasuhara Hideaki 〒101-0032 東京都千代田区岩本町２丁目１−１７ 鈴与日本橋ビル 3F TEL: 03-5823-1570 E-mail: yasuhara@dline.co.jp HP: https://www.dline.co.jp ■ISMS(ISO/IEC 27001:2022 / JIS Q 27001:2023) 認証取得 ■ISMSクラウドセキュリティ(ISO/IEC 27017:2015) 認証取得 ============================== [cid:0835f762-3d60-4163-88a0-983b0442e829]<https://outlook.office.com/bookwithme/user/aee2392bf1644911a37a79340e473e86@dline.co.jp?anonymous&ismsaljsauthenabled&ep=bwmEmailSignature> 自分と会う時間を予約する<https://outlook.office.com/bookwithme/user/aee2392bf1644911a37a79340e473e86@dline.co.jp?anonymous&ismsaljsauthenabled&ep=bwmEmailSignature>
