I created a thread a while ago about the problem and followed the suggestions given in the thread. But it did not work. I am posting a new thread here as the servernames and other info are different this time.
I am able to access the sme server by typing 
http://192.168.1.100/ from any machine on the lan.
But I cannot access the server by typing 
http://moon/http://moon/server-manager/http://www.mercury.lan/server-manager/http://jupiter/server-manager/http://jupiter/ etc.,
Please review my server configuration and let me know what the problem is.
Review configuration
Networking Parameters 
Server Mode serveronly 
Local IP address / subnet mask 192.168.1.100/255.255.255.0 
Gateway 192.168.1.1 
Additional local networks 192.168.1.0/255.255.255.0 
DHCP server disabled 
Server names 
DNS server 192.168.1.100 
Web server 
www.moon.lan Proxy server proxy.moon.lan:3128 
FTP server ftp.moon.lan 
SMTP, POP, and IMAP mail servers mail.moon.lan 
Domain information 
Primary domain moon.lan 
Virtual domains moon.lan 
Primary web site 
http://www.moon.lan Server manager 
http://sun/server-manager/ User password panel 
http://sun/user-password/ Email Addresses useraccount@moon.lan
firstname.lastname@moon.lan
firstname_lastname@moon.lan