1.3 Understanding the Interface
When you first start AmTalk, you will be presented with a small button bar which launches the chat window and the received message list. The bar also acts as a message indicator, informing you of the number of received and unread messaes.
To start chatting with someone, you would click on the 'AmTalk' button and the default window that opens gives you access to the address of the user you'd like to speak to. A drop down window (an arrow pointing to a line) which is a history of people you've talked to in the past so you don't have to type their addresses in again.
Underneath that are three buttons.
Many people seem to have problems understanding how the "Locate and Talk" facility in AmTALK works, so I try to give a more thorough explanation.
One of the reasons that the talk protocol went out of fashion recently is tied to the more and more advancing usage of dynamic IP addresses.
Since you must know the exact host name of a party you want to "talk" to, it's nearly impossible to talk to someone which normally uses a dynamic IP address without a means of finding out the address he currently uses.
You can, for example, find this out if you meet in IRC, but it's pretty pointless to use talk if you could use the more efficient DCC CHAT anyway.
AmTALK tried to provide a solution to this problem, the so-called "Locate facility". How does it work?
Let's assume you want to talk to MrFitz, which ISP's has the domain "ifx.net". ifx.net provides dynamic IP addresses to it's users, so everytime MrFitz logs on, he gets a different host name - "ip69.ifx.net", "ip42.ifx.net" etc.
So, when you want to talk to MrFitz, you don't know which address he's currently using. Locate, however, does the trick of asking all of the potential IPs he may be on for a user with the name of "MrFitz", and if you're lucky, the correct AmTALK at the remote end will respond with "Here I am!" and voilá, you know where to talk to.
Actually, in order for "Locate" to work, you must know at least one of the IP addresses that MrFitz normally has - you might have gotten it from the last time you saw him on IRC, or when he "talk"ed to you etc. You can't use "*.ifx.net" or just "ifx.net" as a anchor address to Locate, btw - it must be a valid hostname which results in a IP address record.
Also, you must know the exact username that he uses at his end, because this is the anchor at which the identification takes place. If you try to locate "mike@ip42.ifx.net", you will fail, because his AmTALK will only responds to queries for the username "Mike". The local username is normally equivalent to the email name of the person, or the username in his IRC userhost address. If you are unsure, just ask.
Technically, "Locate" works by assuming that the ISP gives out all his Dynamic IP addresses from within a single Class-C network. It takes the host name you feed to it, masks out the network part and then queries all 254 IP addresses of this net with a short UDP packet bearing the username. If the correct site is hit, it will respond with a acknowledge packet. This is a very brute force approach to the problem, but has the advantage of not relying to any global or ISP-local "talk hostname servers". The bandwidth waste caused by the packet flood is comparable to WWW or usenet comp.sys.*.advocacy hierarchies, and therefore "Locate" should not be used lightly.
Once you've chosen to talk, another window will appear which is the chat window itself:
This is dominated by two sections - the top one which contains what your chatee has to say to you and the lower one which is what you're saying to them. Scroll bars on both allow you to look at what's moved off the top of the screen. In the dragbar at the top is the address of the person you're talking to.
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