curl: (7) couldn't connect to Host と表示される

環境

bash
1# OSバージョン
2$ cat /etc/redhat-release
3CentOS release 6.5 (Final)
4
5# Apacheのバージョン
6$ httpd -v
7Server version: Apache/2.2.15 (Unix)
8Server built:   Jun 19 2018 15:45:13

自ホストからの接続はOK

bash
1# 自ホストからの接続はOK(192.168.1.50)
2$ curl http://192.168.1.50
3<html>
4<head>
5<meta charset="utf-8">
6<title>タイトル</title>
7</head>
8<body>
9本文
10</body>
11</html>
12
13# 80番ポート開放済み
14$ sudo iptables -nL
15Chain INPUT (policy ACCEPT)
16target     prot opt source               destination
17ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           state RELATED,ESTABLISHED
18ACCEPT     icmp --  0.0.0.0/0            0.0.0.0/0
19ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0
20ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0           state NEW tcp dpt:22
21REJECT     all  --  0.0.0.0/0            0.0.0.0/0           reject-with icmp-host-prohibited
22ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0           tcp dpt:80
23
24Chain FORWARD (policy ACCEPT)
25target     prot opt source               destination
26REJECT     all  --  0.0.0.0/0            0.0.0.0/0           reject-with icmp-host-prohibited
27
28Chain OUTPUT (policy ACCEPT)
29target     prot opt source               destination
30
31# netstatで確認すると、IPv4はLISTENしていない
32$ netstat -anp | grep 'LISTEN '
33(No info could be read for "-p": geteuid()=500 but you should be root.)
34tcp        0      0 0.0.0.0:111                 0.0.0.0:*                   LISTEN      -
35tcp        0      0 0.0.0.0:22                  0.0.0.0:*                   LISTEN      -
36tcp        0      0 127.0.0.1:631               0.0.0.0:*                   LISTEN      -
37tcp        0      0 0.0.0.0:43898               0.0.0.0:*                   LISTEN      -
38tcp        0      0 :::111                      :::*                        LISTEN      -
39tcp        0      0 :::80                       :::*                        LISTEN      - # IPv6はLISTEN
40tcp        0      0 :::22                       :::*                        LISTEN      -
41tcp        0      0 ::1:631                     :::*                        LISTEN      -
42tcp        0      0 :::48964                    :::*                        LISTEN      -
43tcp        0      0 :::3306                     :::*                        LISTEN      -

他ホストからの接続はNG

bash
1# pingはOK
2$ ping 192.168.1.50
3PING 192.168.1.50 (192.168.1.50) 56(84) bytes of data.
464 bytes from 192.168.1.50: icmp_seq=1 ttl=64 time=1.24 ms
5  :
6
7# 他ホストからの接続はNG(192.168.1.23)
8$ curl -v http://192.168.1.50
9* About to connect() to 192.168.1.50 port 80 (#0)
10*   Trying 192.168.1.50... No route to host
11* couldn't connect to host
12* Closing connection #0
13curl: (7) couldn't connect to host