Broadcasts on en0 using Host Only Networking

S

simonc

Bit poster
A week or so ago I tried the "Report a problem" function in Parallels and so far, no response. I was kind of hoping since Parallels is such cool SW that they would have a cool attitude towards solving user problems!

Anyway, I have a linux application that broadcasts UDP packets. The virtual machine is set up for Host Only networking.

On the linux side with tcpdump I can see this:
11:14:50.020305 IP 10.37.129.200.12345 > 224.0.0.23.12345: UDP, length 32

On the Mac side I can see this:
19:12:32.565410 IP 192.168.6.102.52100 > 224.0.0.23.12345: UDP, length 32

Where 10.37.129.200 is the VM's ip address and 192.168.6.102 is Mac OSX's ip address on en0 - the real ethernet adapter!

Any other machine on the real LAN also receives these broadcasts.

This seems to me a major flaw in the implementation of Host Only networking in that stuff on that "LAN" escapes into the real world.

Any ideas?
 
Workaround

Hi and thanks for the speedy response!

I can workaround the problem by doing this on the OS X side:

$ sudo ipfw add 3000 deny udp from any to any dst-port 12345

The VMs connected to the Host Only network still see the broadcasts but they are not sent out to the real LAN.

Adding an ipfw entry like this messes with the ability of System Preferences to manage the firewall so ideally this is not the solution.

Also, I am using Build 1970.
 
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