Freecom Technologies MusicPal user manual Multiple internal but only one external IP address

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Freecom MusicPal

Multiple internal but only one external IP address

A second way to overcome this is to have a single device act on behalf of several other devices. Routers are typical examples. You have several PCs connect to the router, but only the router to the Internet. From an internet perspective, there is only one address. This scheme offers the additional benefit of simple firewall-like protection because the internal LANaddresses arenot available to the Internet through the translatedconnection. All incoming inquiries are filtered out by the router. This filtering can prevent intruders from probing your system. However, using port forwarding, you can allow one PC (for example, a Web server) on your local network to be accessible to outside users.

This works like a receptionist at a large office. Nobody knows your number; they all call the main number of the office and are then forwarded by the receptionist to you.

So how does the receptionist know what number to forward the call too? The caller tells

EN the receptionist what name to look for and the receptionist has a listof names and numbers at her disposal so she can translate the name to the phone extension she needs.

On the Internet, it works exactly the same. NAT (RFC 1631) or Network Address Transla- tion allows a single device, such as a router, to act as an agent between the Internet (or "public network") and a local (or "private") network. This means that only a single, unique IP address is required to represent an entire group of computers.

Network Address Translation

Whenyouvisitawebsiteviayourcomputer,yourrouter,ormorespecificallyyourNAT,remem- berswhichcomputerontheinternalnetworkaskedfortheinformation.Whentheinformation (in this case the website you asked for) comes back, the router knows which computer on the internal network to send the information to. This is Network Address Translation or NAT.

Developed by Cisco, Network Address Translation is used by a device (firewall, router or com- puter) that sits between an internal network and the rest of the world. For more information about IP address translation, refer to RFC 1631, The IP Network Address Translator (NAT).

Hosting a server

What If I want to host a server?

For others to be able to view your pictures on your computer, you need to run some type of service or server. A web server such as apache will allow others to securely watch the pictures or files on your site. But how does the NAT of your router know this time to which computer to forward the information?

Sincetherequestcomesfromtheinternet,mostroutersaresetuptodisallowanytrafficgoinginto the internal network. (Firewall protection) In this case, since we want people to be able to see our pictures, we want the router to forward this information. We have to tell the router to do this.

Someone calling from the internet asks your router for a certain "port". This is the same as someone calling the receptionist and requesting a certain person by name. Ports are dis- played as numbers but invariably map to pre described services. For instance, when someone requests a web page, they always ask for the service on port 80, the web server. Through NAT, it is possible to "map" a certain request for a service (a request for a port) to a certain PC on the

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Contents Musicpal Freecom Technologies GmbH Germany Package Contents Dear UserChapter Appendix Technical Support Freecom on the Internet TrademarkSoftware requirements System requirementsNetwork requirements Hardware requirementsCompatible file formats CompatibilityCompatible play-list formats Compatible streaming formatsSafety precautions Advantages of the Freecom MusicPalSoftware features Hardware featuresConnecting / Installing the Freecom MusicPal Hardware LAN Hardware Wlan Freecom MusicPal Connecting / Installing the Freecom MusicPal Chapter  Getting to know the Freecom MusicPal .1.1 Freecom MusicPal Front SideGetting to know the Freecom MusicPal .1. Freecom MusicPal Rear SideFreecom MusicPal Functions OverviewOverview of Internet Radio Overview of ExtrasOverview of Settings Wlan IP LAN IPNow Playing OptionsFavorites Select Add to favoritesInternet Radio Select the category you wantMedia server UPnP Extras Sleep Timer SettingsSelect Use Sleep Timer? Yes Wake-Up Timer Clock Snooze Timer snooze functionSelect Use NTP-Server? Yes Manual configuration of date and time Select which time zone you areSelect Use NTP-Server? No Show Clock Idle Time RSS Feed Use ´Now Playing´ Select between Use ‘Now Playing’ in clock? Yes or NoShow Clock Edit Favorites Wlan Access Point Connecting with hidden Wlan Access Points Menu Select Access Point, select Hidden Access PointWlan Region Select Wlan RegionUsing Dhcp Select Use DHCP? YesExtras Settings RSS Feeds Select Extras SettingsCalling an RSS Feed Select RSS FeedsSelect Extras Settings Html BrowserCalling an Html Browser Select Html BrowserWeather Calling the Weather Stock Quotes Calling for Stock Quotes Select Stock QuotesWorld Clock Calling the World Clock Select World ClockCalendar Calling the Calendar Select CalendarManual configuration of the IP address LAN IP/WLAN IP Select Use DHCP? NoSound Play Mode Bass Boost Output Line-out Boost Select the Line-out Boost menu itemStartup Sound Display Brightness Active Brightness Sleep Timer Brightness Sleeping Language Name Check for Updates Information Features of the Freecom Network Storage Assistant PC Freecom Network Storage Assistant PC/MacAccessing your MusicPal web interface Start recovery procedureRepeat search for available Freecom MusicPal . Features of the Freecom Network Storage Assistant Mac Login Name Admin Password..1 Configure basic settings of your Freecom MusicPal .. Web interface of your Freecom Network Storage deviceConfiguring the Freecom MusicPal through the Web Interface How do I access the configuration menu?  Now Playing Settings Click Automatically synchronise with an Internet time server Manual configuration of time and date RSS Feed Use ´Now Playing´ Edit Favorites Wlan Access Point Click Dhcp Client Manual configuration of the IP address LAN IP/WLAN IP Settings Extras Html Browser Calling an Html Browser Weather Calling the Weather Calling for Stock Quotes World Clock Select Calendar Sound Play Mode Output Startup Sound Display Brightness Active Brightness Sleeping Language Check for Updates Change password AdministrationUpdate Firmware Freecom MusicPal in practical usage What do I need what for?Media server UPnP in connection with the Freecom MusicPal 1 LANWlan Connecting through a router Connecting the Freecom MusicPalDirect connection Configuring the Freecom MusicPal 100Configuring the computer 101102 Subsequent window double-click Internet protocol TCP/IP103 104 105 Using your Mac as media server UPnPHow can I update my firmware? How can I Iisten to Internet Radio?106 107 VTuner Premium Internet Radio ServiceRegistration 108 109 Administration of the Favorites 110111 112 113 Class a Domain Name ServerInternet address classes Class BNetmask 115Subnet Addressing 116 117 IP address shortageNetwork Address Translation Multiple internal but only one external IP addressHosting a server Ethernet Cabling MAC Addresses and Address Resolution Protocol119 Cable QualityYour Guarantee Conditions
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