CMBB/CMAK TCP/IP Crashes Multiplay.....help?

[imported_Little_Black_Devil]

I've been encountering a problem lately, with regards to Combat Mission (both Barbarossa to Berlin AND Afrika Korps) and playing TCP/IP games.
I haven't played CMBO lately to see if it too is afflicted by this.

A friend of mine and I, have been consistently running into the same problem in both games (CMBB and CMAK). Both of us also have the BFC version of both games.

What happens, is we are able to connect, and able to play any given QB, Scenario of Operation for 3-4 turns. On the 3rd or 4th turn, just as I'm downloading the turn and its a sliver away from finishing (according to the graphical "loading-bar") - it crashes the game and my router. Thus - I belive the "problem" is on my end.

I'm then forced to re-boot the router in order to recover my connection to the internet. In addition, loading a saved game, also doesn't seem to help - as whatever its loading in this phase of the game, seems to be the obstacle my machine or router can't get past - thus it still crashes.

I have ports 7022 and 7023 entered for forwarding within my router, and I have the latest software for my router (which is a Linksys BEFSR41). CM seems to be the only thing on my machine that has issues with my router, as all my other software and games work without a problem.

As best I can tell, I've done everything I'm "supposed" to do, and I still get stopped by this problem.

My router, is a recent addition to my machine. Before I used it, I was working off of a switch. Before the router, CMBB gave me no problems, except for the occaisionaly rare crash after a couple hours of gameplay (in singleplay and multi-play). It certainly was not a show stopper like what I'm now encountering (well - insofar as multiplay anyways).
So - what I'm getting at, is that in general, the game runs fairly stable on my machine in single play and I've never encountered this type of crash in single play, which leads me to suspect that this is defenitely a multi-play issue.

The one thing that does have me wondering, is when I think back to the last time I played a PBEM game (CMBO) and, as I recall, the first few turns were small in size, and required little downloading/loading respectively. However, roughly every 3rd or 4th turn - was a "big" turn/file. I'm wondering if there is somethig in this "big turn/file" that is part of the problem as I have noticed, that even in TCP/IP play - the game still loads turns with this "pattern" of seemingly smaller and larger turn/files (a couple of quick loading turns/movies followed by a larger/slower turn/movie).

I also have Norton Systemworks 2003 and Norton Internet Security installed. I have tried disabling Internet Security, and Enabling it - both options seem to have no bearing on the problem I'm running into. I do have to admit, that I haven't tried disabling Norton Anti-Virus while attempting to play CM in multiplay yet - though I doubt it would be affecting anything.

I'm also running WinXP, and have disabled its built-in Firewall alltogether.

So - I was just wondering, if anyone had any suggestions or solutions? (other than reverting back to a switch - which I would really prefer not to do just to play CMBB/CMAK and probably CMBO in TCP/IP)

Thanks smile.gif

[Schrullenhaft]

Is your current software setup on your computer fairly similar to what you were running when you hooked up through a switch ? Are you still using the same ISP you were when you hooked up with a switch ? What type of ISP connection is this, cable, DSL or other ? What device is on the WAN side of your router ?

If your software environment stayed the same and the only difference is the router, then I'd pretty much assume that it is the router that is having the problem. Do you have problems with anything else regarding access to the internet or downloading large files ?

How did you update the firmware for your router ? Is this a 'version 3' of the BEFSR41 or something earlier ? Is the 'Power' or 'Diag' light blinking on the router ? These indicate a firmware problem, but this also means that you probably would be unable to use your router at all for your connection; so they're unlikely. If this is not a version 3 router, then you have the 1.45.7 firmware, correct ? This version fixes a problem with fragmented packets arriving out of order.

You may need to adjust the MTU (Maximum Transmission Unit) settings of your router. Though this most often applies to email and other problems, it may be helpful here. The following is a 'copy & paste' of Knowledgebase article KB10934351 on the Linksys website:

To find the proper MTU Size, you'll have to do a special ping of the destination you're trying to go to. A destination could be another computer, or a URL (try your opponent's computer if it is up).

1. Click on the Start button, then select the Run option.

2. In the "Open" field type in command (If you're using Windows 2K/NT/XP use CMD instead)

3. Once the window opens, you'll need to do a special ping. It should be formatted:

ping [url] [-f] [-l] [MTU value] [Enter] an example would be:

ping yahoo.com -f -l 1472 <result = fragmented packet>

ping yahoo.com -f -l 1462 <result = fragmented packet>

ping yahoo.com -f -l 1452 <result = reply>

You should always start at 1472 and work your way down by 10 each time. Once you get a reply, go up by 2 until you get a fragmented packet. Take that value and add 28 to the value to account for the various TCP/IP headers. For example, lets say that 1452 was the proper value, the actual MTU size would be 1480, which is the optimum for the network we're working with.

4. Once you've found the optimum MTU size open up your browser, usually Internet Explorer, which is located on your desktop (Or on the Start menu in Windows XP)

5. Once Internet Explorer has opened input http://192.168.1.1/Filters.htm into the "Address" bar

6. You will be prompted for a User Name and Password. Leave the User Name blank and input admin as the password then click OK

7. Once you've done this you should find your self on the Filters tab. Scroll down to the bottom and look for "MTU". Enable the option and input the optimum value you got earlier. So for our example this would be 1480. After that value has been inputted click Apply then Continue and you're done.

NOTE: If you don't have a "MTU" option please goto http://www.linksys.com/download and select the model number of the router you have and the OS you're using. Then click on "Firmware" and follow the upgrade instructions.


In the end you may just want to note down your unique settings for the router and do a 'reset' on it. Make the changes necessary to make the connection and see if this helps or not.

[imported_Little_Black_Devil]

First of all - thank you very much for the very prompt and detailed response. smile.gif

I'll try and answer your questions as best I can. I'm hoping my buddy will post here later today as he is more networky savy than I'am, so perhaps he can fill in the gaps.

Is your current software setup on your computer fairly similar to what you were running when you hooked up through a switch ? Yes

Are you still using the same ISP you were when you hooked up with a switch ? Yes

What type of ISP connection is this, cable, DSL or other ? DSL

What device is on the WAN side of your router ?
Not sure - I'll have to get back to you on that.

Do you have problems with anything else regarding access to the internet or downloading large files ?
No, though before I entered specific ports for specific programs such as MSN messenger or even Outlook, they couldn't work properly.

How did you update the firmware for your router ? Its a version 3 Router, and it came with the latest firmware.

You may need to adjust the MTU (Maximum Transmission Unit) settings of your router. I checked on this, and it was already set as high as it could go, before I started running into fragmented packets.

I haven't tried a complete reset of my router yet.

However, we spent pretty much the entire evening last night tinkering with this, and I think we either "fixed it" or found a work around.

For some reason, the game seems to crash my router once the "firing and fighting" begins in any game. It seemed, that so long as my buddy and I didn't expose each others troops to the otherside where firing could begin - the game would continue to run without a problem. However, as soon as the first firing began, uploading the next portion of the turn would always precipitate a crash of my router just as the turn appeared to have finished uploading.

However, what we found that was of real interest, was that when we both had our computers listed in each of our routers respective DMZ - no problems at all. This wasn't exactly surprising, but it did help us narrow where the problem was originating from.

We then tried a multi-play game with just my friends computer listed within his router's DMZ - and my computer NOT in a DMZ, it still worked without crashing my router. We found it peculiar, that something in my buddy's router SEEMED to be crashing my router (though we're speculating).

Anyhow, I'm hoping my buddy will log on here and correct me, or clarify what I've said in techie-networkanese. ;)
Perhaps he could also post his pertinent router stats which might be of use to you?

Does any of this make any sense? ;)

Thanks again smile.gif

[slewfoot]

Little_Black_Devil's buddy here.

A couple more things - I have a firewall (PC-Cillin) on my computer which had the tcp port 7023 open - both directions. We had both computers in the DMZ of our respective routers, his router still locked. I then added ports 7022 and 7024 to my firewall...everything worked from this point on.

Took both computers out of the DMZs, and crashed. Put Little_Black_Devil's computer in DMZ, crashed his router. Took his computer out of the DMZ and put mine in my router's DMZ and everything worked.

This narrows it down to some configuration on my router - haven't had time to look too closely yet.

What I find interesting, is that a configuration issue on MY end causes HIS router to hang...terminating all of his internet connections, and pointing our trouble-shooting in the wrong direction.

I am also surprised that the only port mentioned in the manual (7023) is not the only port required to be opened...I suspect this is NOT a battlefront caused issue, but more likely something that microsoft has done in the TCP/IP stack in recent upgrades - automatic fail-overs to another port or something like that perhaps.

The reason I suggest MS is that we were able to play CMBB a while back with our "original" configurations, but CMBB now has the same problems as we have encountered with CMAK.

[imported_Little_Black_Devil]

Well...to complicate matters, last night we conducted more testing - and it appears that what we thought was working, i.e. - leaving Slewfoot's computer in a DMZ no longer worked, and there have been no additional changes on my end.

So...it seems we may be back to square one. :(

We do suspect however, that CMBB/CMAK requires more ports than 7022, 7023 and 7024 to be open, in order for the game to work properly (in TCP/IP Multi-play).

Any other suggestions or points?

Thanks smile.gif

[Schrullenhaft]

Can the PC-Cillin firewall be disabled temporarily without uninstalling it ?

As far as I know CM only needs TCP Port 7023. That is the port that CM is listening and communicating on. The code specifies this port and nothing else (to my knowledge). I'm not sure why people claim that they need additional ports (7022, 7024) since CM isn't using them directly (it's "two-way" over 7023). I'm not sure what Microsoft could have done to change this since they would have to be hashing up the port table in order for software services to work with ports they weren't originally assigned to or programmed for.

What did you find out about the temporary DMZ solution that didn't work. Did it not work for long (but worked longer than previous sessions) or did it not work in another session, etc. ?

What router are you using slewfoot ? Could you put your computer in the DMZ and turn off the PC-Cillin firewall (I know... this completely opens up your computer for attack).

[slewfoot]

Firewall can be disabled (can't remember if we tried that or not).

We had both computers in respective DMZs and it was working the first night...then the next night it didn't work with the same setup.

My router is a SMC Barricade model SMC7004ABR.

I've just downloaded a packet sniffer to try and see what's going on (more to confirm which ports are being used.

There may be something up with my ISP as the battlefront website is extremely slow for me - and only the battlefront web site - on both of my computers. All other web sites are fine.

[slewfoot]

Schrullenhaft, thanks for your time man.

We put both computers in their DMZ and I shut down my personal firewall completely (PC-Cillin) and turned the packet sniffer on (it's a trial version, but I may purchase it in the near future)

Anyway, what I found is that CMAK uses ONLY port 7023 - ALL communications between my computer and Little_Black_Devil's were on port 7023 ONLY. There was some other stuff (some of which scares me - I'll have to investigate it).

We were able to play for several turns (10-15)before crashing, and it still locked Little_Black_Devil's router.
There must be something else hindering the communications on that port or blocking it all together...still checking things out.

Will keep you posted.

[slewfoot]

New data:

Little_Black_Devil is now temporarily located at an internet connection without a router.

I hosted, through a router (only port 7023 opened/forwarded), and PC-Cillin firewall was enabled (port 7023 opened) on Windows 2000.

Little_Black_Devil had Norton internet security and Norton anti-virus enabled. Windows XP firewall was disabled.

Everything worked fine.

Earlier we tried and failed in the same method, but Little_Black_Devil was getting around 20% packet loss (checked this out through teamspeak), and the game crashed the same as before. He checked his patch cable (re-seated) and packet loss became acceptable (0.02%).

With no packet loss everything worked fine. This makes me lean back to some configuration issue on his original router...we'll have to test this out once he's located back at home.

It was an excellent opportunity for us to trouble-shoot be reducing the equation to eliminate possible problem areas.

Will keep you posted.

[imported_Little_Black_Devil]

Just to clarify on one small point;

I was only ever getting that packet loss at my new and temporary location. (Same Computer - nothing, other than location and lack of a router to connect through has changed).

Web-pages, and any other internet related applications, including other games - were suffering noticeably under the packet loss.
I could "tell" by these other applications and games - that everything was performing noticeably slower - and seemingly, had no reason to.

In any event - with that fixed, as Slewfoot pointed out, we were able to get a few (CMAK) games going without issue, which does indeed lead us to believe there is an issue with my router.

Thanks again for your help Schrullenhaft. smile.gif