Ubuntu20.04でApacheにアクセス出来ない時の対処法

とある検証のためにUbuntu20.04にApacheをインストールしたのですが、アクセスできず20分ほど格闘して無駄の時間を過ごしてしまったので備忘録として残そうと思いました。

結論

iptablesで開放すれば解決しました。

デフォルトの状態

ubuntu@apache-fluentd:/var/log/apache2$ sudo /sbin/iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination
ACCEPT     all  --  anywhere             anywhere             state RELATED,ESTABLISHED
ACCEPT     icmp --  anywhere             anywhere
ACCEPT     all  --  anywhere             anywhere
ACCEPT     udp  --  anywhere             anywhere             udp spt:ntp
ACCEPT     tcp  --  anywhere             anywhere             state NEW tcp dpt:ssh
REJECT     all  --  anywhere             anywhere             reject-with icmp-host-prohibited

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination
REJECT     all  --  anywhere             anywhere             reject-with icmp-host-prohibited

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination
InstanceServices  all  --  anywhere             link-local/16

Chain InstanceServices (1 references)
target     prot opt source               destination
ACCEPT     tcp  --  anywhere             169.254.0.2          owner UID match root tcp dpt:iscsi-target /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */
ACCEPT     tcp  --  anywhere             169.254.2.0/24       owner UID match root tcp dpt:iscsi-target /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */
ACCEPT     tcp  --  anywhere             169.254.4.0/24       owner UID match root tcp dpt:iscsi-target /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */
ACCEPT     tcp  --  anywhere             169.254.5.0/24       owner UID match root tcp dpt:iscsi-target /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */
ACCEPT     tcp  --  anywhere             169.254.0.2          tcp dpt:http /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */
ACCEPT     udp  --  anywhere             169.254.169.254      udp dpt:domain /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */
ACCEPT     tcp  --  anywhere             169.254.169.254      tcp dpt:domain /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */
ACCEPT     tcp  --  anywhere             169.254.0.3          owner UID match root tcp dpt:http /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */
ACCEPT     tcp  --  anywhere             169.254.0.4          tcp dpt:http /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */
ACCEPT     tcp  --  anywhere             169.254.169.254      tcp dpt:http /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */
ACCEPT     udp  --  anywhere             169.254.169.254      udp dpt:bootps /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */
ACCEPT     udp  --  anywhere             169.254.169.254      udp dpt:tftp /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */
ACCEPT     udp  --  anywhere             169.254.169.254      udp dpt:ntp /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */
REJECT     tcp  --  anywhere             link-local/16        tcp /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */ reject-with tcp-reset
REJECT     udp  --  anywhere             link-local/16        udp /* See the Oracle-Provided Images section in the Oracle Cloud Infrastructure documentation for security impact of modifying or removing this rule */ reject-with icmp-port-unreachable

port80の開放を行う

おっとコマンドが無いみたいです。

ubuntu@apache-fluentd:/var/log/apache2$ firewall-cmd --add-service=http --zone=public --permanent

Command 'firewall-cmd' not found, but can be installed with:

sudo apt install firewalld

firewall-cmdのインストール

ubuntu@apache-fluentd:/var/log/apache2$ sudo apt install firewalld -y

再度ポート開放にチャレンジ

ubuntu@apache-fluentd:/var/log/apache2$ sudo firewall-cmd --add-service=http --zone=public --permanent
success
ubuntu@apache-fluentd:/var/log/apache2$ sudo firewall-cmd --reload
success
ubuntu@apache-fluentd:/var/log/apache2$

これで無事アクセス出来ました。。
Ubuntuってデフォルトでiptables有効なの？良く分からん・・・