Ssh
儘管防火牆鎖定,但仍有數千次傳入 SSH 連接嘗試
因此,我的伺服器受到了數千次 SSH 登錄嘗試的衝擊。Fail2ban 正在擷取並禁止它們 - 但我的收件箱讓我擔心,它會在收件箱中填滿警報。這是我所看到的範例:
May 28 15:26:09 sshd[4908]: input_userauth_request: invalid user test [preauth] May 28 15:26:09 sshd[4908]: pam_unix(sshd:auth): check pass; user unknown May 28 15:26:09 sshd[4908]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=<<SNIPIP>> May 28 15:26:11 sshd[4908]: Failed password for invalid user test from <<SNIPIP>> port 41344 ssh2 May 28 15:26:11 sshd[4908]: Received disconnect from <<SNIPIP>> port 41344:11: Bye Bye [preauth] May 28 15:26:11 sshd[4908]: Disconnected from <<SNIPIP>> port 41344 [preauth]
有趣的是,當我嘗試使用以下方式進行連接時:
ssh test@myserverip -p 41344
我的連接嘗試最終超時,並且我在 auth.log 中沒有看到任何條目 - 這是我期望發生的情況,因為我已經通過 UFW 鎖定了機器防火牆:(旁注:我已經在非標準埠上執行 ssh )
ufw status verbose Status: active Logging: on (low) Default: deny (incoming), allow (outgoing), disabled (routed) New profiles: skip To Action From -- ------ ---- Anywhere DENY IN 144.202.55.196 Anywhere DENY IN 188.53.140.190 Anywhere DENY IN 185.50.197.159 Anywhere DENY IN 206.189.197.133 Anywhere DENY IN 61.175.121.73 Anywhere DENY IN 8.30.124.149 Anywhere DENY IN 193.105.134.45 Anywhere DENY IN 139.129.14.230 Anywhere DENY IN 37.247.96.111 22 DENY IN Anywhere 2200/tcp ALLOW IN Anywhere 25/tcp ALLOW IN Anywhere 80,443/tcp (Nginx Full) ALLOW IN Anywhere 2246 ALLOW IN Anywhere 2812 ALLOW IN Anywhere 2247/tcp ALLOW IN Anywhere 19999/tcp ALLOW IN Anywhere 82/tcp ALLOW IN Anywhere 22 (v6) DENY IN Anywhere (v6) 2200/tcp (v6) ALLOW IN Anywhere (v6) 25/tcp (v6) ALLOW IN Anywhere (v6) 80,443/tcp (Nginx Full (v6)) ALLOW IN Anywhere (v6) 2246 (v6) ALLOW IN Anywhere (v6) 2812 (v6) ALLOW IN Anywhere (v6) 2247/tcp (v6) ALLOW IN Anywhere (v6) 19999/tcp (v6) ALLOW IN Anywhere (v6) 82/tcp (v6) ALLOW IN Anywhere (v6)
所以我的主要問題是,當我無法登錄時,怎麼可能有人甚至有機會嘗試登錄埠 41344?
這是遠端端連接的源埠。連接到您這邊的埠 22(或任何您的 SSH 守護程序正在偵聽的埠)。
每個網路套接字都由一個源地址和埠以及一個目標地址和埠組成。源埠由源作業系統隨機選擇。