为何与连接不到远程oracle数据库?

shunji

Oracle816+red hat Linux6.2环境,
本地主机(ip是192.168.0.20)通过电话线+Moden拨号连通远程主机(ip是122.147.160.12),现网络已经连通,ping 122.147.160.12连通到远程主机,但是在测试连接数据库时却无法接通,
tnsnames.ora文件内容如下
ZB.WORLD =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 122.147.160.12)(PORT = 1521))
(CONNECT_DATA = (SID = ora)
)

但是在测试tnsping zb.world时,却一直停留在如下提示:
attempting to contact (ADDRESS = (PROTOCOL = TCP)(HOST = 122.147.160.12)(PORT = 1521))

既不提示成功也不提示失败!

另,telnet 122.147.160.12时也无法连通远程主机,只提示如下:
Trying 122.147.160.12...
Connected to 122.147.160.12 (122.147.160.12).
Escape character is '^]'.
接收等待长时间也无反应

请教各位高手,这是什么原因呢?

shunji

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