[R-SIG-Mac] snow cluster - unable to open connection

Simon Urbanek simon.urbanek at r-project.org
Sat Sep 9 17:31:54 CEST 2006

On Sep 6, 2006, at 12:28 PM, Martin Renner wrote:

> Thank you for the replies, Luke and Sean!
> turning off the firewall on each and every machine did finally  
> allow me to start the cluster across all my machines. Keeping the  
> firewall on would be desirable, however. Using tcp wrappers I can  
> restrict access to local IPs - although I loose the bonjour-names  
> (machineA.local, etc - need to use IP numbers instead). When the  
> firewall is turned on, the console.log records "Firewall Tool:  
> Error, Start Port (600011) invalid!"

^^ that's of course nonsense - TCP ports are 16-bit, so there is no  
such thing as port 600011 as the firewall software correctly tells  
you. If you take it modulo 2^32, you'll get port 10187 which is what  
SOCK in snow uses by default (FWIW: it is use-configurable, so you  
can use any port you want). This can be easily verified when you look  
at the existing connections (e.g. local one):
iX:urbanek$ lsof|grep ^R|grep TCP
R         8842 urbanek    4u    IPv4 0x03a7b3f0        0t0      TCP> (ESTABLISHED)
R         8855 urbanek    3u    IPv4 0x025c2e10        0t0      TCP> (ESTABLISHED)
So opening port 10187 may possibly do the trick. You still need to  
make sure that the firewall allows the inverse  - connect to an  
outgoing port - many do so for UDP, but I suspect only few do so for  
TCP by default.


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