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Sidewinder G2 6.1.1 Administration Guide - Glossary of Technical ...

Sidewinder G2 6.1.1 Administration Guide - Glossary of Technical ...

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RIP with the <strong>Sidewinder</strong> <strong>G2</strong> NOT using transparent IP addressing<br />

RIP with the<br />

<strong>Sidewinder</strong> <strong>G2</strong><br />

NOT using<br />

transparent IP<br />

addressing<br />

D-8 Configuring Dynamic Routing with RIP<br />

6. <strong>Sidewinder</strong><strong>G2</strong>_c, receives the IP frame for the Telnet server, checks the<br />

route, has a route, and sends it up to the internal TCP servers. The<br />

<strong>Sidewinder</strong> <strong>G2</strong> TCP services checks the frame and discovers this is not a<br />

TCP connection request and that it there is not currently a session with<br />

the client. Because <strong>of</strong> this, TCP services builds a ‘TCP reset’ frame and<br />

sends it back to the client.<br />

Note: This causes the current Telnet session to be lost. However, when the Telnet client<br />

opens another session to the server, that connection request will get sent to<br />

<strong>Sidewinder</strong><strong>G2</strong>_c, which will go through all the above steps and establish a NEW session<br />

with the Telnet server.<br />

So what happened to the sessions between <strong>Sidewinder</strong><strong>G2</strong>_b and the<br />

client, and <strong>Sidewinder</strong><strong>G2</strong>_b and the server? These sessions will timeout<br />

according to what has been configured for the Telnet proxy<br />

inactivity timer. Currently this defaults to 2700 seconds, or 45 minutes.<br />

Unless the Telnet server also has a connection time-out, the session<br />

will remain between the two systems until the time-out occurs, at<br />

which time the proxy closes both sessions.<br />

What will happen when the route between Router_a and<br />

<strong>Sidewinder</strong><strong>G2</strong>_b becomes available again? The Telnet client sends the<br />

frame to Router_d which will send an ‘ICMP Redirect’ back to the<br />

client telling it to communicate through Router_b. The client will<br />

resend the frame to Router_b, which forwards it to the <strong>Sidewinder</strong> <strong>G2</strong>.<br />

Again the <strong>Sidewinder</strong> <strong>G2</strong> has received a frame for which it is not in<br />

session, and it will send a ‘TCP reset’ back to the client, causing the<br />

client to again close the session. As far as the client is concerned the<br />

Telnet server has unexpectedly closed the session. And again, if the<br />

client opens a new session all will be fine. But remember the sessions<br />

are timing out between <strong>Sidewinder</strong><strong>G2</strong>_c and the Telnet server.<br />

Important: The administrator should change this Telnet idle session timer to<br />

something more reasonable such as 10 minutes.<br />

The assumption for this discussion is that the Telnet server must be<br />

able to identify the Telnet clients IP address. The above configuration<br />

would not allow this, the Telnet server will see all sessions from<br />

CorpCity network as originating from the <strong>Sidewinder</strong> <strong>G2</strong>. In Figure D-<br />

4 as with Figure D-3, in order to pass any traffic through the<br />

<strong>Sidewinder</strong> <strong>G2</strong>, some proxy or server must be configured and<br />

enabled.

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