Net Send - anyone?

[Ryan]

Anyone use Net Send broadcasts to inform users of stuff (reboots, issues, etc)?

 

I'm aware that enabling it causes (or used to cause) problems with malicious popups from the internet and other sources. Just wondering if anyone has it enabled and uses it.

[Joedetic]

We used to use it to notify users when servers were going down for maintenance etc or when machines would be forced a reboot to install software at the end of the day.

 

What they have it for at my uni is to tell users when there's going to be a tutorial in a room and give you 5 minutes notice to bugger off. It does this in the "open access" areas of the uni that are also used for teaching. It must be on some kind of a scheduled task or something.

 

The other uses I've seen is where there's a shared partition on a suite of computers for saving simulations to etc using Matlab, Multisim, Maple and Pro Engineer drawings etc, and the computers are due to be re-imaged, to remind students to save work....also periodic reminders of assignment submission times at the faculty reception.

 

As a user of a couple of networks that have had this style of popup, I've never had any malicious ones from the internet. The thing to do would be to enable it on your machine and leave it for a week or so and see imo.

[Ryan]

enable it on your machine and leave it for a week or so and see imo

Think i'll give that a bash before enabling it across the board

 

Incidentally, i remember using and abusing 'net send' from the command prompt at uni as a sort of rudimentary messenger service between mates Until the uni cottoned on to it, that is.

Edited February 15, 2008 by Ryan

[srochford]

As a user of a couple of networks that have had this style of popup, I've never had any malicious ones from the internet. The thing to do would be to enable it on your machine and leave it for a week or so and see imo.

 

Given a half decent firewall, you're not going to get problems from the internet. What you will get is problems from kids bring in programs which do the equivalent of net send.

 

If this becomes an issue and you want to use net send then it's possible to leave the messenger service stopped and write a script which:

 

connects to each computer on the network

starts the messenger service

sends a message

waits a bit for the message to be received

stops the messenger service again

[Michael]

I used net send in the Windows 2000/ Windows XP SP1 period, but of course times have moved on from then. Windows XP SP2 and Windows Server 2003 disable the service by default. I've never really looked into re-enabling the service although it's easily done using AD.

[cookie_monster]

You shouldn't receive any popups from the internet as your perimiter firewall should filter that.

 

We have the messenger service enabled on staff PC's and dissable it on student PC's, as they can't run exe's we haven't had any issues with students sending messages. They used to use a .bat file that used command.com but sortware restrictions sorted that.

[Ryan]

All useful stuff, thanks guys.

 

I'm leaning towards using this for domain-wide broadcasts because, as we know, very few people actually check their chuffing emails regularly!

[Geoff]

very few people actually check their chuffing emails regularly!

 

That's their problem, not yours.

[DMcCoy]

I stopped using it after I subnetted everything, as it doesn't work

[Joedetic]

How're you subnetted out of interest? Seems a little odd that MS wouldn't support subnet masks other than /24 /16 or /8 for netsend? Are you doing fun stuff with vlsm?

[SYNACK]

When I was at Uni they monitored the net send system I believe by using the message queuing app on the server. I was called in and grilled by the then system admin about my seemingly harmless batch file that could fire off 500 messages to the same computer in about 10 seconds.

 

Amusing to think that I am now the guy that has to prevent that kind of stuff.

[DMcCoy]

How're you subnetted out of interest? Seems a little odd that MS wouldn't support subnet masks other than /24 /16 or /8 for netsend? Are you doing fun stuff with vlsm?

 

I didn't feel like running a wins server on every vlan to avoid the lack of broadcast. It affects browser too as they can't see the servers, not that browsing directly to the server doesn't work, just don't get a nice computer list.

[Joedetic]

Ahhhh. VLANs are fun *lols quietly to himself in the corner*

[RyRobbo]

Ahhhh net send... How i loved annoying my family on the home network. I havn't tried it in school but i can access command.com with a simple batch file, and there is nothing stopping me from typing "net start "messenger"". If it did work and i got caught the techys would hand me lengthly network ban.

[cookie_monster]

i can access command.com with a simple batch file

 

Exactly why they should be using software restriction policy.

[Ryan]

Quick question: can the messenger service be enabled through GP? Or otherwise remotely? I've been using ARI for some remote stuff, but enabling services doesn't work too well (as in, 'at all').

[ZeroHour]

Yep it can as I had to do it here after sp2 disabling it by default

Computer Config->Windows Settings->Security Settings->System Services

 

We use net send * {MSG} and software restriction policy so it all works well.

[Ryan]

Lovely, ta dude