Missing Network Devices/Computers

[TheSchaft]

Irritating problem: When I fire up my systems, about 30% of the time one or more of the computers or the Network drive will be missing from the list of devices on the LAN and be inaccessable except from some programs. I have to power down all three computers then power them back up to get everything to show up and be accessable.

Configuration: Linksys router, WD Worldbook 1T drive connected via Ethernet, Toshiba laptop connected via wireless, two desktop systems connected via Ethernet. One desktop running Win 7 MSDN distro, other two running RC 7100. Computers use WD network drive for backup and Outlook 2007 mail. Computers and WD have fixed IPs.

 

[DocBrown]

32 bit or 64 bit computers ? or a mixture of both ?

How did you set up the network ?

As a Win7 HomeGroup or as a business work network ?

" Doc "

 

[SquonkSC]

Do you have upnp enabled in the router?

 

[TheSchaft]

Sorry - should have included that info.

All computers are 32 bit, network is set up as a "home network", none are using HomeGroup - they are all in a workgroup called "HOME", and set to "Use user accounts and passwords to connect to other computers." Sharing is set for files and printers.

 

[TheSchaft]

Nope, UPNP is not enabled on the router.

As I said originally, 70% of the time everything is visible. It's just occasionally that one or more of the elements are missing.

 

[SquonkSC]

Nope, UPNP is not enabled on the router.

As I said originally, 70% of the time everything is visible. It's just occasionally that one or more of the elements are missing.

Enable upnp, it helps windows discovering network items, and contrary to some paranoid stories on the internet, it is perfectly safe.

Good luck.

 

[TheSchaft]

Thanks Squonksc, I'll give that a shot and report back.

 

[DocBrown]

Discovery On ?

 

[TheSchaft]

Doc Brown - Yup, looks like your picture, except that 128 bit encryption is set.

I think it may be related to a delay in responding from the Linux-based WD network drive and the wireless laptop - they are the only ones that go missing.

Right now, here's what shows:
my desktop - my desktop, my wife's desktop, the WD (no laptop)
wife's desktop - my desktop, her desktop, the WD (no laptop)
Laptop - itself, my desktop, my wife's desktop (no WD)

In order to get the laptop to show on the desktop systems, and the WD to show on the laptop, I need to power all but the WD down, wave the magic chicken, and hope for the best.

 

[HRM]

I am by no means a win7 expert, but issues very similar to this were solved by using static IPs (I would just use the same address that they were assigned by the server). That took care of most of it, but I also set my wifes computer to be the master browser since it was rarely rebooted and mine and the laptops were. That fixed it for me. Before I set this, my XP Pro machine often was the master browser and my shares and the other machines took forever to be available.

some info about it, BTW, my master browser here is XP home. This seemed to help with boot times and shares/machines instantly being available with me figuring it elimitated the browser election process.


Preferred Master Browser


Now, there could be very good reasons this is a bad idea that I am not aware of, but I offer this as a way I was able to solve this with XP. YMMV and if one of the gurus suggests something else, do that first.

You can always set the browser back to auto or whatever the default was. Pick a machine that is always on and hardly ever booted (if you have one).

Best of luck

 

[TheSchaft]

HRM, et. al. -

Looks like I found the problem. I had COMODO set too tight, and it was not allowing "system" to do multicast. I loosened up the restrictions in the COMODO firewall and it looks like that has solved the problem.

Thanks for all the help and suggestions. I need to study up more on the firewall stuff, it would appear - embarassing as I do computer security for a living - <sigh>

 

[logicearth]

HRM, et. al. -

Looks like I found the problem. I had COMODO set too tight, and it was not allowing "system" to do multicast. I loosened up the restrictions in the COMODO firewall and it looks like that has solved the problem.

Thanks for all the help and suggestions. I need to study up more on the firewall stuff, it would appear - embarassing as I do computer security for a living - <sigh>

To be honest, there is no reason to be running a firewall on a computer in your own private network. The firewall in the router alone is enough. And if you really wanted to be running a firewall just use the one built into Windows 7. Its more then capable. The built in one also has the advantage of only turning on when you join a public network, that is when you really need it.

 

[TheSchaft]

logicearth -

I partially agree with what you say.

The router keeps the LAN hidden and catches most of the bad activity. However, I've found that MS Media Player has a bad habit of sending information someplace, for some reason, so I like to stop it.

There are some other programs that like to "phone home" also, and I like to be able to control what goes out of my system. Just paranoid I guess. <shrug>

 

[logicearth]

logicearth -

I partially agree with what you say.

The router keeps the LAN hidden and catches most of the bad activity. However, I've found that MS Media Player has a bad habit of sending information someplace, for some reason, so I like to stop it.

There are some other programs that like to "phone home" also, and I like to be able to control what goes out of my system. Just paranoid I guess. <shrug>

You can do all that with the built in firewall, just set it to block from the properties in "Windows Firewall with Advanced Security". Or go into the Outbound Rules section and set Windows Media Player, down in the list to block.

 

[SquonkSC]

It's a common misconception to think a hardware firewall is enough.

It only protects you from unsolicited incoming packets.

It does not protect against solicited incoming packets.

This means a program like a trojan, keylogger or a program that just want's to send info to the internet can easily bypass the routers firewall.


A tip for TheShaft.

When troubleshooting network problems, ALWAYS turn off all software firewalls.

From your first post I deducted you had good knowledge of networking, so I wrongly assumed you would have thought of turning firewalls off.

Nice to learn that your problem is solved.

Greetz

 

[TheSchaft]

squonksc -

I like to try to solve these sort of problems while keeping the parameters as close to what I run as possible.

I could have turned off the software firewall (COMODO) and found that the problem was solved, but the real source of the problem would have been buried.

Since I obviously have too much time on my hands, I elected to narrow the problem down to what in COMODO was causing the issue as opposed to just turning off the firewall and declaring a victory.

I appreciate your suggestions on this.

 

[logicearth]

It's a common misconception to think a hardware firewall is enough.

It only protects you from unsolicited incoming packets.

It does not protect against solicited incoming packets.

This means a program like a trojan, keylogger or a program that just want's to send info to the internet can easily bypass the routers firewall.

Yet the malware is already on the computer with full control over that computer, which in turn can make any changes it wants which could allow it to bypass any security software running making the whole point moot.

The best defense is not to get any of that on your computer in the first place.

 

[TheSchaft]

You can do all that with the built in firewall, just set it to block from the properties in "Windows Firewall with Advanced Security". Or go into the Outbound Rules section and set Windows Media Player, down in the list to block.

I agree that the built-in firewall, especially when used with Windows 7 Firewall Controller, can do what you say - I ran it and set it to only allow incoming Windows Media Player access. I'm just more comfortable with COMODO since I've been using it for a couple of years - <shrug> different strokes.

I think that the Windows 7 security approach has improved greatly over time, and look forward to their future changes. I may go back to the embedded firewall and Windows 7 Firewall Controller in the future, assuming it is as easy to manipulate as I find COMODO to be (probably because I'm more familiar with it.)

 

[SquonkSC]

Yet the malware is already on the computer with full control over that computer, which in turn can make any changes it wants which could allow it to bypass any security software running making the whole point moot.

Nonsense.

You are only right in case one never checks the firewall rules to look for anything fishy.

That's why you are right in 99% of the cases.


@Theshaft,

I can see your point, but you make a wrong jump in your thoughts. IMHO

If you had disabled the firewall, you would instantly know the problem lies somewhere in there, thus saving you time looking in other places.

From there you could examine the firewall further.

If turning it off made no difference, you could instantly rule it out.

Greetz

 

[TheSchaft]

Ahh, Sorry, I should have explained it better.

From experience, I realized almost immediately that the problem had to be in the software firewall, so I tackled that first.

How did I come to that conclusion? Again my error in not explaining it better. The problem occurred most often (but not always) with the systems running COMODO.

My wife's system rarely had the problem, but was running the most vanilla 7100 RC of the three - windows firewall with no restrictions (I had toasted her system when I re-partitioned it from XP - long story, not relevant)

HOWEVER, the problem would occur with her system on occasion - see earlier posts - so I had to bound the problem.

It turns out that if you have the type of incompatability I posted about the only solution is to turn off all the systems and start again (waving the magic chicken is optional.)