When you can receive DCC, but cant initiate a dcc send or chat, the problem is usually one of two things: mIRC isnt getting the correct ip for you, or you are blocking the ports needed with your firewall/router/network. (NOTE: if your employer/school/isp is doing the blocking,you can go beg your sysadmin, which is pretty much an exercise in futility and will prolly make them cranky. If there happens to be a hole in the way the tech ppl set it up, or there is a way to evade their wishes, we will not help you find or exploit it)
You and the other person should check for any error msgs in your status window, like file type blocked or needing to dccallow. Try with more than one person/file type. The problem could be on the others persons end. Check your mIRC options to be sure you/them arent blocking dcc (file/options/dcc, look under ignore there too, and file/options/general/lock or in recent mIRC versions: view/ options/dcc and view/options/ other/lock).
Check for an ip mismatch by typing /dns yournickhere and then typing //say $ip and compare the two. If they arent the same, type /localinfo -u and then try to DCC send.
Make sure that mIRC is getting the external ip for you, not your internal network ip. You will also need to forward a range of ports for mIRC to use and then set those ports in mIRC's options under file/options/dcc/options (in recent versions of mIRC, it will be view/options/ connect/options and click on the advanced button ) where you see the default of 1024-5000. (Any externally initiated connections, like identd port 113 and dcc ports in options need to be forwarded in router to the lan ip of the mirc computer.)
You may also consider shutting down (temporarily) any AntiVirus programs you have running, more specifically those that have "Auto protect" or "Real time protection" features. Norton Antivirus 2005 has an 'Internet Worm Protection' feature that will block DCC, you can disable this in NAV's Options section.
XP firewall help: on Merlin's site
and here when using this tutorial, please note that in v6.14 dcc ports moved to connect/options, click on advanced button
For help with the Windows XP Service Pack 2
Windows Firewall, which differs slightly from the original Windows XP Internet Connection Firewall, please see this website
at microsoft.com. You can also see this guide
, which was specifically written for mIRC by Collective.If you are setting a port rather than making a complete exception for mIRC, choose 'TCP'.
Linksys: Linksys help http://www.linksys.com/tech_helper/advanced.html
OR Linksys & DCC (basic) - http://www.practicallynetworked.com/support/linksys_router_help_pg4.htm#mIRC
scroll down to (3) advanced router setup also check http://www.dlink.co.uk/search.asp
click on your equipment then look on left frame for config download or install guide. also this web page
Note, you can find guides for port forwarding for many more routers at http://www.portforward.com/routers.htm
so check that out if the above doesn't help you! (Thanks Danthmandoo for that link)
Also note that some routers (like some of the Netgear ones) seem to dislike port 6667, try changing to a different server port. Also be sure you have the latest firmware for your router.
General networking and ICS help: http://www.practicallynetworked.com/howto/http://www.dalantech.com/http://www.ircworks.com/ics.htmhttp://www.borg.com/~chuck/using.htm
DSL: You may be able to web or telnet in to adjust the default settings. Ask your provider, and finding out what router they use will be a help to you. You can telnet into some, with a text-only configuration, and you can web into others with password protected access. Some have built in firewall/routers that you may or may not be able to adjust. The provider may have set up very restrictive settings, or they may be that way by default until you change them. If you can web-administer your unit, the fix will vary depending on the device in question. Get the model number of your unit, and go to the maker's website. See if it is "integrated router" or "integrated firewall" type. Settle in, and start reading the configuration documents at the makers site
Note that some settings can only be adjusted from the ISP level, while others could be adjusted by the user, but only if the ISP allows the user access.
Cable:Some cable users have resolved their DCC problem by doing the following:
1. Be sure the cable provider doesn't have you firewalled.
2. While disconnected, in File>Options>Connect>Local info, under on connect always get, clear both the local host and the greyed out ip address boxes.
3. In Windows control panel>internet options>connection, change both modem and LAN settings to "automatically detect"
Satellite: I've been told that some, like directpc and directway one have a packet size and distance issue from your computer to the satellite to their *station* back to the satellite and back to the other computer and dcc send isnt likely to cooperate
its possible scripts/addons could interfere with things. unload them, turn them off or try with a new clean copy of mIRC in a new directory)