☰

Wie debugge ich einen Server, der seine DHCP-IP nicht freigibt?

tag-icon • tag-icon networking debian dhcp
Wie debugge ich einen Server, der seine DHCP-IP nicht freigibt?

Es sieht so aus, als würde mein Server immer wieder nach einer DHCP-Adresse fragen, aber alte nicht freigeben. Zuvor war er direkt mit meinem ISP verbunden und hielt Tausende von DHCP-Leases (das hätte möglicherweise einen stadtweiten DoS-Angriff verursacht).

Der Server kann weiterhin auf das Internet zugreifen. Das Problem verursacht keine Verbindungsprobleme für den Server, aber alle anderen können die beanspruchten IP-Adressen nicht verwenden.

Um das Problem zu isolieren, habe ich es ans LAN angeschlossen. Wenig überraschend war der IP-Pool des Routers erschöpft. Alle IP-Adressen waren vom lokalen Host aus erreichbar (ich kann ihn anpingen, <1 ms Verzögerung), aber nicht von außen.

Ich habe nicht viel Erfahrung mit dhclientoder damit, wie ein Server mit dem Erwerben/Freigeben von IP-Adressen umgeht. /etc/network/interfacesist unverändert, außerallow-hotplug ens5

Das Problem könnte begonnen haben, als ich entweder

  • ersetzt sendmaildurch postfix( apt-get install postfix, sonst nichts)
  • ausgeführt apt-get upgrade(Kernel und einige PHP-Module aktualisiert, sonst nichts)

Ich habe keine benutzerdefinierten Skripte auf dem Server. dmesgist sauber. Es ist ein Webserver und das meiste, was ich mache, geschieht entweder vor Ort nginxoder in der Site (Wordpress).

Wie fange ich überhaupt an, das zu debuggen? So etwas ist mir in der Vergangenheit noch nie begegnet.

root@placeholder-not-actual-hostname:~# uname -a
Linux placeholder-not-actual-hostname 4.9.0-5-amd64 #1 SMP Debian 4.9.65-3+deb9u2 (2018-01-04) x86_64 GNU/Linux

Ausgabe von ip a:

root@placeholder-not-actual-hostname:~# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: ens5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether e0:cb:4e:48:4e:28 brd ff:ff:ff:ff:ff:ff
    inet 192.168.249.2/24 brd 255.255.255.255 scope global ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.3/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.4/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.5/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.6/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.7/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.8/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.9/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.10/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.11/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.12/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.13/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.14/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.15/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.16/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.17/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.18/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.19/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.20/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.21/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.22/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.23/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.24/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.25/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.26/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.27/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.28/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.29/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.30/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.31/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.32/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.33/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.34/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.35/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.36/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.37/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.38/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.39/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.40/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.41/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.42/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.43/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.44/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.45/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.46/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.47/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.48/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.49/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.50/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.51/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.52/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.53/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.54/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.55/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.56/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.57/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.58/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.59/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.60/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.61/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.62/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.63/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.64/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.65/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.66/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.67/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.68/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.69/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.70/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.72/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.73/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.74/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.75/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.76/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.77/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.78/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.79/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.80/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.81/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.82/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.83/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.84/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.85/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.86/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.87/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.88/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.89/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.90/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.91/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.92/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.93/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.94/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.95/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.96/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.97/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.98/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.99/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.100/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.101/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.102/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.103/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.104/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.105/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.106/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.107/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.108/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.109/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.110/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.111/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.112/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.113/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.114/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.115/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.116/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.117/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.118/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.119/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.120/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.121/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.122/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.123/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.124/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.125/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.126/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.127/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.128/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.129/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.130/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.131/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.132/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.133/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.134/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.135/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.136/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.137/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.138/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.139/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.140/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.141/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.142/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.143/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.144/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.145/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.146/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.147/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.148/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.149/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.150/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.151/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.152/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.153/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.154/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.155/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.156/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.157/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.158/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.159/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.160/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.161/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.162/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.163/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.164/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.165/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.166/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.167/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.168/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.169/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.170/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.171/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.172/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.173/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.174/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.175/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.176/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.177/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.178/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.179/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.180/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.181/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.182/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.183/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.184/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.185/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.186/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.187/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.188/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.189/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.190/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.191/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.192/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.193/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.194/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.195/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.196/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.197/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.198/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.199/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.200/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.254/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet 192.168.249.71/24 brd 255.255.255.255 scope global secondary ens5
       valid_lft forever preferred_lft forever
    inet6 fe80::e2cb:4eff:fe48:4e28/64 scope link
       valid_lft forever preferred_lft forever
3: wls1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 00:25:d3:cd:e0:4f brd ff:ff:ff:ff:ff:ff
4: tun0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN group default qlen 100
    link/none
    inet 10.8.0.1/24 brd 10.8.0.255 scope global tun0
       valid_lft forever preferred_lft forever
    inet6 fe80::f3c8:a059:15d5:5ec7/64 scope link flags 800
       valid_lft forever preferred_lft forever

Der gesamte Inhalt von /etc/network/interfaces. /etc/network/interfaces.d/ist leer.

root@placeholder:~# cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto ens5
allow-hotplug ens5
iface ens5 inet dhcp

Antwort1

Ich habe das Problem gelöst.

Ich habe in meiner Antwort angemerkt, dass der Erwerb von IP-Adressen problemlos funktioniert, die Freigabe von Leases jedoch nicht.

Ich habe nachgeschaut /etc/dhcp/und zwei interessante Verzeichnisse gefunden:

root@placeholder:~# ls -lah /etc/dhcp/
total 744K
drwxr-xr-x   4 root root 4.0K Feb 17 08:00 .
drwxr-xr-x 104 root root 720K Feb 18 11:57 ..
-rw-r--r--   1 root root 1.4K Nov 26  2016 debug
drwxr-xr-x   2 root root 4.0K Aug 21  2010 dhclient-enter-hooks.d
drwxr-xr-x   2 root root 4.0K Feb 17 13:46 dhclient-exit-hooks.d
-rw-r--r--   1 root root 1.7K Dec 25 22:41 dhclient.conf

Ich habe gerade herausgefunden, dass dhclientes tatsächlich Hooks für den Fall gibt, dass 1.) eine DHCP-Lease erworben und 2.) eine DHCP-Lease freigegeben wird. Die .dVerzeichnisse enthalten Bash-Skripte, die ausgeführt werden, wenn die genannten Ereignisse ausgelöst werden.

Da der Server Probleme mit der Freigabe von DHCP-Leases hatte, habe ich nachgesehen dhclient-exit-hooks.d. Tatsächlich war da ein fehlerhaftes Skript. sendmailDarin war ein Skript, das immer fehlschlug, obwohl es 0 zurückgab (fehlendes Verzeichnis, da sendmaildeinstalliert).

verwandte Informationen