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<TITLE>RE: looking up ip global IP address from inside LAN</TITLE>
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<P><FONT SIZE=2>> From: Justin Holzer [<A HREF="mailto:justin@ptctraining.com">mailto:justin@ptctraining.com</A>]</FONT>
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<P><FONT SIZE=2>> Say for example, I have cable modem service, and have several machines</FONT>
<BR><FONT SIZE=2>> sharing this connection via a store-bought broadband router. </FONT>
<BR><FONT SIZE=2>> Now say I'm running squeak on one of the networked machines, ie. 192.168.1.1.</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Is it possible for me to get the global IP address of my </FONT>
<BR><FONT SIZE=2>> cable modem, ie 216.109.125.71, without having to send a </FONT>
<BR><FONT SIZE=2>> packet outside of my local network?</FONT>
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<P><FONT SIZE=2>Hmmm... it should be possible, if we assume the meaning of local</FONT>
<BR><FONT SIZE=2>is physical. Not sure if you can do this in Squeak though...</FONT>
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<P><FONT SIZE=2>Since each network interface has its' own IP address, devices on your</FONT>
<BR><FONT SIZE=2> 'local' network (LAN) will each have an address (hopefully in the</FONT>
<BR><FONT SIZE=2>same subnet :-)). A router on your LAN will have a local IP</FONT>
<BR><FONT SIZE=2>address and the other side of it (often called the WAN interface)</FONT>
<BR><FONT SIZE=2>attached to your cable modem will have a different IP address </FONT>
<BR><FONT SIZE=2>that it gets from your ISP.</FONT>
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<P><FONT SIZE=2>What you want is most likely the WAN address from your router.</FONT>
<BR><FONT SIZE=2>Several other methods have been mentioned so here's a third</FONT>
<BR><FONT SIZE=2>possibility:</FONT>
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<P><FONT SIZE=2>OSProcess + traceroute (or tracert in Windows) (Unless someone has </FONT>
<BR><FONT SIZE=2>written a traceroute utility you can use within Squeak ?)</FONT>
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<P><FONT SIZE=2>In theory you should be able to get the address from traceroute</FONT>
<BR><FONT SIZE=2>because it SHOULD be the next address following your router's LAN </FONT>
<BR><FONT SIZE=2>address when you use traceroute... [I'm at work so I can't try/verify </FONT>
<BR><FONT SIZE=2>it myself right now...] (And assuming your router isn't blocking ICMP</FONT>
<BR><FONT SIZE=2>(the protocol used by traceroute))</FONT>
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<P><FONT SIZE=2>The real "trick" is going to be keeping packets within your</FONT>
<BR><FONT SIZE=2>network... with traceroute you have to be "aiming" at something</FONT>
<BR><FONT SIZE=2>to get it to work. If you can control "hops" in whatever traceroute</FONT>
<BR><FONT SIZE=2>utility you are using it might be possible. I don't recall how</FONT>
<BR><FONT SIZE=2>'hop counts' are measured - between routers or between network </FONT>
<BR><FONT SIZE=2>interfaces...</FONT>
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<P><FONT SIZE=2>HTH</FONT>
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<P><FONT SIZE=2>-Andy- </FONT>
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