[Info-vax] SSH/SCP sessions hanging for 7 minutes while reading from "/dev/random"

[Arne Vajhøj]

On 9/29/2021 6:31 PM, sphowes wrote:
> I am hoping someone may be able to help resolve an issue while
> opening an SSH or SCP session on an OpenVMS 7.3-2 cluster.
> 
> When a session is initiated to or from the server, the connection
> will hang for ~7 minutes before finally opening the connection and
> asking for a password.
> 
> While running an 'ssh -D 99' I can see that all of the delay time is
> being spent while trying to read from "/dev/random".  Each iteration
> of "Starting read from /dev/random" is taking a minute to timeout and
> then returning with "Opening /dev/random failed" and then it tries
> again for a total of 7 total tries.
> 
> At the end of this section the SSH/SCP connection opens fine.
> 
> Does anyone know what it is actually trying to open when it
> references "/dev/random"?   Is there any way to make a configuration
> change to work around this?   Or limit the number of times it loops
> the read or reduce the 60 sec read timeout?
If you define a logical DEV to point to a directory
and you place a file RANDOM. in that directory, then
I expect it to read from that file.

But that would not be good for the randomness so I will
not recommend that.

I am puzzled about why it tries to read from /dev/random
on VMS - it should try and get some random bytes via
SYS$GETJPIW, SYS$GETSYI and SUS$GETDVIW - or something
like that.

Arne