Ed. note: This page was rescued from ircworks.com when it got discontinued. Links may or may not work, it is maintained here just for the information contained on this page itself. -Jolo


mIRC and ICS

dumped by Wayne3, phrased by Jeepster

General Introduction
IP addresses
mIRC Settings
Tutorial/Reference URLs 

Good Info On Other Sites
LinkSys: http://www.practicallynetworked.com/support/linksys_router_help_pg4.htm#mIRC
LinkSys Tutorial: http://kareno.net/LinkSys/
NetGear Router: http://jason-n3xt.org/melio/MIRCNETGEAR.htm
Win XP & mIRC: http://toidyman.net/xp-dcc/
Proxies: http://www.mirc.co.uk/help/proxies.html
ICS/Firewalls/Wingate: http://www.borg.com/~chuck/using.htm

More Info& Tutorial links at bottom of the page


Internet Connection Sharing (ICS) is becoming very popular at both home and work.  One of the drawbacks to this has been loss of Direct Client to Client (DCC) capability while using mIRC.  Usually the individual on the home network could receive DCC chats and file sends, but they could not initiate them.  This is due to the nature of the Client To Client Protocol (CTCP) that DCC derives from. (offsite ctcp/dcc protocol info)

Not being an Local Area Network (LAN) kind of user, I decided it was time to find someone who is knowledgeable and willing to spend some time sharing ideas on how to make mIRC more functional when used on a LAN, Home Network, or ICS environment.  Wayne3 kindly consented to sharing his experience and ideas.


An ICS system usually consists of a internet connection via an internet service provider and a gateway computer that connects to the ISP via dial-up modem, cable modem, or DSL modem. 

Then other computers are connected to the gateway computer using Network Interface Cards (NIC).  This is often done via a "hub" that enables one or more connections from other computers to the gateway computer. 

Not all Home Networks use a hub.  However this info should be useful to them as well.

Internet Connection Sharing Graphic


Here we have three computers that use a single connection to the internet.  Simple, eh?

The problem occurs with DCC because as far as the internet is concerned, all three computers are using the same IP address, the IP assigned to the gateway computer by the ISP. 

And to complicate it, the port that the client computer opens when it starts a DCC chat or file send isn't reported correctly to the computer at the other end of the internet.

Ultimately, DCC sends and chats fail!

Windows users, including Win98, Win ME, Win2000 pro can restore their DCC capability.  It involves Port Mapping.  No, not Port Scanning!  Port mapping allows the gateway computer to pass info correctly between the client computers and the internet.  The simple fix is NAT32.  It costs a few bucks, between $25.00 and $50.00 US, depending on which version you purchase.  All info here is without guarantee or warranty of any sort, either by myself or Wayne3, we are simply sharing ideas and experiences that will hopefully benefit other IRC users.

Port Mapping/NAT32

<Wayne3> Ok, ICS will not work with DCC chat over a lan without a Port Mapper.
<Jeepz-> okay ..
<Wayne3> Let me grab the URL for a good freeware port mapper.
Freeware Port Mapper URL
<Wayne3> If they install a port mapper, they will only be able to use DCC with DCC Server on the specific port they set :)
<Jeepz-> so they need to set a specific port in mIRC options?
<Jeepz-> and the same port on their server?
<Wayne3> Port in their DCC Server in mIRC options needs to be same as the one being mapped on the gateway machine.
<Jeepz-> any URL for doing the gateway setting .. I suppose that varies depending on what software they use
<Wayne3> Right ICS Wizard it auto, I recommend they drop $30 and get NAT32 *
<Wayne3> NAT32 will allow DCC chat without any extra software 
<Wayne3> NAT32 is better by 1000% *
<Jeepz-> okay .. so they use nat32 to do their port mapping on the gateway computer .. set the client computer (workstation) mIRC to use DCC server and same port .. ?
<Wayne3> Now if they are using a router it all work fine with DCC chat, even across subnets and domains because the header information will contain the correct address for the packets.

{* note: bold and italics added by Jeepster for reader's benefit}


Concerning firewalls:

<Wayne3> Okay firewall information.
<Jeepz-> k .. 
<Wayne3> Most firewalls will block all unauthorized connections, but for example ZoneAlarm allows you to add applications that are allowed to do everything they want.
<Wayne3> Users will want to look into that.
<Wayne3> k, so always have them check that. If they can have them disable the firewall and try to DCC to see if that is the issue.
<Wayne3> np, another thing is to have the user always check with their ISPs about Firewall, blocked ports, etc..
<Wayne3> Some ISPs block port 80, 110, 23, 22, 25, etc.. to stop users from running servers :)
<Wayne3> Those are low level ports and only mail, web, ftp, and those types of daemons would use bind to those ports :)
<Jeepz-> right .. basic trouble shooting technique
<Wayne3> Also ask them if they are using a HUB, a high collision rate on the network can cause packets not reach their destination.
<Jeepz-> okay ..
<Wayne3> Causing slow DCC, or Unable to Connect Errors a few times, then all of the sudden work
<Wayne3> then fail again a couple times, then work, etc...
<Jeepz-> erratic performance
<Jeepz-> I see .. though many of these folks are on smaller home based nets .. not all mind you
<Jeepz-> but many .. that's getting much popular these days .. and a source of many questions
<Jeepz-> so that would possibly show up if they have a hub and maybe five or six machines .. or does it need a much larger network to become a problem?
<Wayne3> If you get someone who cannot use mIRC at all with their client machines make sure they can access LAN resources and browse the web before trying to fix their mIRC problem!!
<Wayne3> Sorry had to throw that in ;)
<Jeepz-> oh yeah .. no prob ..
<Wayne3> No I have experienced that problem before at friends house with a 3 LAN network
<Jeepz-> so small size isn't immune to it .. good to know



Equipment Recommendations:

<Wayne3> LinkSys 10BaseT 5 Port Hub (Home LAN) is very popular and is a shit Hub and will collide every 5 seconds if more than one machine is access something.
<Jeepz-> ah .. yeah, I see folks using LinkSys often .. must be inexpensive
<Wayne3> Yep :)
<Jeepz-> you have any suggestion for better performance while watching pennies?
<Wayne3> They build nice industry equipment, but their home base products blow
<Wayne3> I only recommend Cisco, Netgear, and 3Com networking hardware :)
<Jeepz-> k .. I use 3Com here .. so pay for what you get basically
<Wayne3> Intel Pro is one NIC I make exception for because its a good card :)
<Wayne3> But it uses a 3com based chipset ;)
<Jeepz-> ah ..
<Wayne3> Yep, what you pay is what you get .. "If its to good to be true it is"
<Jeepz-> Cisco's good stuff .. but pricey ..
<Wayne3> Worth every penny, best there is.
* Jeepz- nods
<Wayne3> A Q&D solution to a lot of collisions on a LAN is to get another NIC on the Gateway machine :)
<Jeepz-> two NIC on the gateway .. one to the net .. the other to the LAN?
<Wayne3> Right, one to their ISPs equipment and one to their HUB or home Router.
<Jeepz-> k ;-)


IP Assignments:

<Wayne3> Make sure they have their IPs on there networks correct, with ICS Windows won't bitch if two machines have the IP of on the same subnet
<Wayne3> I cannot count how many times I have typed the same IP into two clients.
<Jeepz-> does their ISP provide them with multiple IP's or is there a generally used for protocol assignment?
<Wayne3> I mean private IPs, like 192, 168, 172(or is it 176), 10.
<Wayne3> On a LAN in the same subnet, ICS won't bitch at you for that, and your basic features like email, web, and irc will work but DCC will not
<Jeepz-> I see .. so it is a specific group that would be recognized within the network but not viable for NET connection .. dunno if I'm phrasing that so it makes sense
<Wayne3> Yes, they are IPs reserved for LANs
<Jeepz-> okay .. that makes sense.
<Wayne3> 10 machines -> hub -> router (with a public IP) this saves companies for having to buy IPs for every single client machine.


mIRC Settings:

<Jeepz-> more along the line of how the user would set mIRC itself .. 
<Wayne3> Well really, if your initial network setup is done well, there is no 
special setup for mIRC needed.
<Jeepz-> hmm .. okay. but they are going to wonder what to put in the 
Userhost and IP fields, or what to set for Method. Or at least what to expect to 
see there if everything goes right 
<Wayne3> Leave them blank and user server as the method, it should populate with the correct information
<Jeepz-> okay .. that makes sense .. 
<Wayne3> If everything goes right, you can expect mIRC to function just as if you 
had a modem and where using dial-up connection :)


Tutorials, Info, Reference URLS:

<Wayne3> Umm let me dig up a URL real quick for LAN newbies
<Wayne3> ICS Tutorial(s) and HowTos - http://www.generation.net/~hleboeuf/ics.htm
<Wayne3> http://www.microsoft.com/technet/network/ipvers6.asp <-- this makes good reading also 
<Wayne3> http://www.landfield.com/faqs/internet/tcp-ip/resource-list/ <-- list of TCP/IP books and resources (good for LAN/WAN information)
<Wayne3> one more .... http://www.books.mfi.com/lan/LANTut3rdEd.html
<Wayne3> last one -> http://www.wizard.com/users/baker/public_html/NetTutor.html
<Wayne3> the last one I think is more along the lines your looking for
<Jeepz-> great .. thanks much .. appreciate you sharing your expertise!

Port Mapping URLs:
     NAT32:       http://www.nat32.com/
     Port Mapper: http://www.analogx.com/contents/download/network/pmapper.htm

Other Good Sources of Info:





Ed. note: This page was rescued from ircworks.com when it got discontinued. Links may or may not work, it is maintained here just for the information contained on this page itself. -Jolo