PostgreSQL安裝后Navicat客戶端連接報錯：Could not connect to server:Connection refused(0x00002740/10061)
經常使用PostgreSQL數據庫的用戶，在用Navicat客戶端連接服務器端時，報錯：
Could not connect to server：Connection refused(0x00002740/10061)
Is the server running on host “xxx.xxx.xx.xx” and accepting
TCP/IP connetions on port 5432?
此問題產生的原因有：
1.host“xxx.xxx.xxx.xxx”不存在，此時客戶端ping此IP應不是不通的
2.Host“xxx.xxx.xxx.xxx”存在，客戶端ping此Ip地址能ping通，但是此主機並未安裝PostgreSQL數據庫
以上兩個原因好理解，下面還有幾個原因，后台查看ps -ef|grep postmaster如下：
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[root@CM-126 pgsql_9.2.2]
# ps -ef|grep postmaster
root 793 32595 0 14:30 pts
/0
00:00:00
grep
postmaster
postgres 32762 1 0 13:50 ? 00:00:00
/usr/local/pgsql/bin/postmaster
-D
/usr/local/pgsql/data
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3.host“xxx.xxx.xxx.xxx”存在，客戶端ping此Ip地址能ping通，此主機上也安裝了PostgreSQL數據庫，監聽端口是5432，但客戶端填寫時而不是5432，如果5432也不正確，就確認下數據庫監聽的端口，后台用“netstat -anp|grep postmaster”命令查看下
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[root@localhost pgsql]# netstat -anp|grep postmaster
tcp
0
0
0.0
.
0.0
:
5432
0.0
.
0.0
:* LISTEN
14430
/postmaster
tcp
0
0
:::
5432
:::* LISTEN
14430
/postmaster
udp
0
0
127.0
.
0.1
:
1316
127.0
.
0.1
:
1316
ESTABLISHED
14430
/postmaster
unix
2
[ ACC ] STREAM LISTENING
14603833
14430
/postmaster /tmp/.s.PGSQL.
5432
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4.host“xxx.xxx.xxx.xxx”存在，能被客戶端ping通，PostgreSQL數據庫在主機上已安裝，但$PGDATA/data/目錄下的配置文件postgresql.conf中關於監聽地址配置為：
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listen_addresses =
'localhost'
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或者
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#listen_addresses = '*'
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如果是此種情況，有兩種方法可以解決此問題。
第一種：修改配置文件postgresql.conf
此時只需將監聽地址改為：
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listen_addresses =
'*'
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然后，重啟(/etc/rc.d/init.d/postgresql restart)PostgreSQL即可
第二種：配置文件postgresql.conf不做修改
保持postgresql.conf不變，轉而修改PostgreSQL的啟動腳本postgresql:
原來啟動時命令行為
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su
- $PGUSER -c
"$DAEMON -D '$PGDATA' &"
>>$PGLOG 2>&1
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現改為
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su
- $PGUSER -c
"$DAEMON -i -D '$PGDATA' &"
>>$PGLOG 2>&1
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啟動后一般為
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/usr/local/pgsql/bin/postmaster
-i -D
/usr/local/pgsql/data
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啟動時加上-i選項，意思就是允許TCP/IP連接
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[root@localhost pgsql]
# /usr/local/pgsql/bin/postmaster --help|grep TCP/IP
-i
enable
TCP
/IP
connections
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5、防火牆開啟也會造成此種現象
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[root@cloudera135 ~]
# iptables -L
Chain INPUT (policy ACCEPT)
target prot opt
source
destination
ACCEPT udp -- anywhere anywhere udp dpt:domain
ACCEPT tcp -- anywhere anywhere tcp dpt:domain
ACCEPT udp -- anywhere anywhere udp dpt:bootps
ACCEPT tcp -- anywhere anywhere tcp dpt:bootps
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ACCEPT icmp -- anywhere anywhere
ACCEPT all -- anywhere anywhere
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
ACCEPT all -- anywhere 192.168.122.0
/24
state RELATED,ESTABLISHED
ACCEPT all -- 192.168.122.0
/24
anywhere
ACCEPT all -- anywhere anywhere
REJECT all -- anywhere anywhere reject-with icmp-port-unreachable
REJECT all -- anywhere anywhere reject-with icmp-port-unreachable
REJECT all -- anywhere anywhere reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT)
target prot opt
source
destination
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此種情況若解決，只需關閉防火牆即可
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[root@cloudera135 ~]
# service iptables stop
iptables：清除防火牆規則： [確定]
iptables：將鏈設置為政策 ACCEPT：nat mangle filter [確定]
iptables：正在卸載模塊： [確定]
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若不想關閉防火牆，也可以改變防火牆規則以解決此問題。
注意：3、4兩種情況下，$PGDATA/pg_hba.conf文件中的配置為
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# TYPE DATABASE USER ADDRESS METHOD
host all all 0.0.0.0
/0
trust
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