Bind ppp0 connection to use the same IP

kevinguerreiro · 03-08-2017, 03:22 AM

Hello Linux question forum,

I'm more a windows user, and just started linux a few months ago.
My question is, is it possible to bind a vpns connection let's say ppp0 to use always the same ip?

I have a linux pptp vpn server, and when someone connects to the vpn, i need that that user to have the same ip ( that is possible by setting it on the chap file) and the same pppX number.

Is that possible ?

Thanks Allot
Kevin

ferrari · 03-08-2017, 12:54 PM

I've never done this (as usually I leave pptpd to allocate IP addresses), but I know from reading man pptpd.conf that the delegate option can be used

Quote:

delegate
delegates the allocation of client IP addresses to pppd(8).
Without this option, which is the default, pptpd manages the
list of IP addresses for clients and passes the next free
address to pppd. With this option, pptpd does not pass an
address, and so pppd may use radius or chap-secrets to allocate
an address.

localip ip-specification
one or many IP addresses to be used at the local end of the
tunnelled PPP links between the server and the client. If one
address only is given, this address is used for all clients.
Otherwise, one address per client must be given, and if there
are no free addresses then any new clients will be refused.
localip will be ignored if the delegate option is used.

remoteip ip-specification
a list of IP addresses to assign to remote PPTP clients. Each
connected client must have a different address, so there must be
at least as many addresses as you have simultaneous clients, and
preferably some spare, since you cannot change this list without
restarting pptpd. A warning will be sent to syslog(3) when the
IP address pool is exhausted. remoteip will be ignored if the
delegate option is used.

then I assume (but open to correction) /etc/ppp/chap-secrets is configured with the IP address allocation like this

Code:

# Secrets for authentication using CHAP
# client        server  secret            acceptable local IP addresses
jim             aaa.bbb smith             192.168.5.100

kevinguerreiro · 03-08-2017, 01:57 PM

Hello Ferrari,

Thanks for your reply.

I Have managed to do what i needed.

After a little scripting i got it working. What i did was a script in /etc/ppp/ip-up, to verify what ip the ppt connection has,since i defined the usernames with fixed ip's, it makes the correct static route that i need for that specific connection.

If anyone need the scipt or a different explanation don't hesitante to ask.

Best Regards
Kevin Guerreiro

Jjanel · 03-12-2017, 07:11 AM

Welcome to LQ! One minor thing you could do, to help future searchers find this,
is to mark it as 'Solved', via ThreadTools at top

Sounds like you are doing GREAT with Linux! Best wishes...