[R-sig-hpc] R hangs when connected via VPN [incl. minimal example]

[Marius Hofert]

Dear expeRts, 

This is a similar post as on R-SIG-MAC [I didn't receive an answer there] and
R-help. On the latter mailing list, Duncan Murdoch suggested to contact a
package maintainer and ask for help. I contacted Rich Calaway from Revolution 
Analytics. After a few trials he suggested to write to R-SIG-HPC. 

The problem is that if [and only if] I am connected via VPN, R "hangs" on executing
the minimal example below.
After contacting Rich Calaway, I realized that [after executing the minimal example
line by line] the makeCluster call is the problem. So if I am connected via
VPN, the following line is not executed properly:
cl <- makeCluster(mpi.universe.size(), type ="MPI") 

Is this a known issue?
The "red button" in the R Console is dark red [normal behavior if R is running], 
so R tries to do something, but cannot succeed. CPU goes up to 100%... This is quite
annoying when working on a server but testing code locally at the same time. 

I'm running R version 2.12.1 (Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)) 
on a MacBook Pro under Mac OS X 10.6.6. I am connected to a server via a VPN client 
[Cisco AnyConnect; same happens with Apple's internal VPN connection].

Any help is highly appreciated.

Cheers, 

Marius 

Minimal example:

library(doSNOW) 
library(Rmpi) 
library(rlecuyer) 
library(foreach) 

cl <- makeCluster(mpi.universe.size(), type ="MPI") 
tmp <- clusterSetupRNG(cl, seed=rep(1,6)) 
registerDoSNOW(cl) 

counter <- 0 
res <- foreach(k = 1:1000) %do% { 
    counter <- counter + 1 
} 
tmp <- stopCluster(cl) 

unlist(res)

library(doSNOW) 
library(foreach)

cl <- makeCluster(mpi.universe.size(), type ="MPI") # (loads Rmpi)
tmp <- clusterSetupRNG(cl, seed=rep(1,6)) # (loads rlecuyer)
registerDoSNOW(cl)

counter <- 0
res <- foreach(k = 1:1000) %do% { # same problem with dopar
  counter <- counter + 1
}
tmp <- stopCluster(cl)

unlist(res)