The following configuration should fix problems between tnsname, the hosts file and browser:

tnsnames.ora (file)

[sql]DBNAME_DEV =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.99.98)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = ORADB1)
)
)
DBNAME_PRD=
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.99.99)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = ORADB2)
)
)[/sql]

hosts (file)
[text]#127.0.0.1       localhost
192.168.99.98    WEB1
192.168.99.99    WEB2[/text]

internet browser

under network/connection > LAN > Do not use proxy for:

[text]192.168.99.*;web1,web2[/text]