Are there any valid reasons to place an adapter in promiscuous mode?

[Madpup]

Other than network monitoring? One of our vendors has a medical software package running on a node on our network to post process CT scanner images for teleradiology. The network adapter is set in promiscuous mode and the vendor claims that the overhead required to "lock down" their product would be prohibitive if they need to dial in later and do maintenance.

I have two concerns. First, is it good to have a network adapter in promiscuous mode attached to a system with a direct dial in via PC Anywhere?

Second, the data load on this network is enormous. Some of these imaging data sets can contain 1,000 or more 512K images. At any one time there might be two or three transfer operations of files of 500MB going on at any one time. Will having a this system set in promiscuous mode slow down the traffic on the subnet or network?

Thank you in advance for your help.

 

[Peter]

Promiscous mode makes the network device pull ALL traffic into the system it's in. Meaning that it doesn't cause any extra net traffic, it just causes a massive amount of local traffic in the box.

You do this if you want to monitor all traffic on the net segment. If in doubt about the purpose, isolate the thing in its own net segment, with a router inbetween that doesn't forward anything but packets specifically targeting this thing - or just put it onto a self learning switch that does the same.

 

[AbsolutDealage]

agreed. The promiscuous adapter will simply cause a load on the connected machine, it will not outwardly affect the network at all. Just get a decent switch to isolate out the node and you should have no problems.

 

[Peter]

... and if the company's remote servicing still works then, they'll be proving themselves liars.

 

[Madpup]

Pardon my ignorance, but....

Would this excess load cause a slowdown in the transmission times of large data sets to the node?

Would it affect system performance in other ways?