Eggheads: Problem with DCC CHATting to eggdrop 1.6.15 from same Internet connection

Paul T Wang eggdrop at
Sun Sep 14 18:21:35 CST 2003

>  RE: Problem with DCC CHATting to eggdrop 1.6.15 from same Internet
>  connection
> I'm using the eggdrop bot v1.6.15...

To summerize your problem, your home LAN is on NAT with DHCP or Static
(which probably doesn't concern eggdrop) with a gateway/router.

What are uncertain:
Which device is exposed to the Internet?
Does the gateway/router honor your IRC client as a server?

What might be the problem:
In normal route tables, your own Internet address (example: is
automatically routed as a loopback. It acts like However, because
your network setup is unknown, I can't comment on this possible problem.

1. Your IRC client on Computer A sends a DCC CHAT
    request via IRC with your external IP and external port.
2. Your eggdrop sitting on Computer B telnets to
3. IF Computer B is directly connect to the Internet
THEN it loops external_ip right back to itself...
        Effectively, it telnets<external_port>
        which doesn't work
ELSE it connects to <external_ip>:<external_port>
        4. *Some routers are not happy with an external
             loopback (requests to connect to itself from
            internal to external) and might do strange things*
        5. Assuming your router/gateway is smart and handles
            the request properly, it will connect right back to...
            err... which local IP is the server? The router has to
            know Computer A:port X is the server in order to
            forward the packets to Computer A:port X.

> Is there a particular port that DCC CHAT uses?

Consult with your IRC client manual. Most IRC clients are able to specify a
DCC port range for CHAT and SEND. If you are behind a NAT router, you must
make use of this feature to chat/send things out.

More information about the Eggheads mailing list