[pptp-server] Lots of Concurrent PPP interfaces

[Stan A. Rogge]

Anyone out there ever configured a server for quite a lot of concurrent
VPNs?

I have managed to get 100 concurrent connections, but pppd will not build an
interface beyond ppp99.

I get this error:

kernel: ppp: dev_alloc_name failed (-23)
kernel: ppp: ppp_alloc failed
pppd[1722]: ioctl(TIOCSETD): Too many open files in system(23)


I have already adjusted a few things in the kernel, like:

netlink.h    MAX_LINKS    2048
limits.h    NR_OPEN    2048
limits.h    OPEN_MAx    1024
tty.h    MAX_NR_CONSOLES    2047

In the kernel's .config I have:

CONFIG_UNIX98_PTYS=y
CONFIG_UNIX98_PTY_COUNT=2048

I am using linux-2.2.13 with ppp-2.3.8 with the microsoft patches for their
gay encryption.  My setup works ok.  Been using it all for quite a while for
both PPTP and SSH VPNs, at least thats my story.

My last assigned device to pppd was pts/100.  I have 235 processes on the
box.

My target is to see how many concurrent PPP interfaces can be achieved
concurrently.  I want around 1300 or so, but am stuck with PPP0 - PPP99.

If anyone has been here before, please share your wisdom.  I really have not
seen any info on this in the traditional documentation.  I have look around
at some of the code for PPP, but do not see this particular limit.  I fear
it may be ioctl stuff.

Thanks in advance.