Hello,
second try. I am running into a serious problem with a VPN setup that I sort of need to get going 
I run one office and a data center cluster, all hooked up with mikrotik and for a project we are integrating one, then in a month another external location.
On the first I have a problem. It is a normal DSL hookup. The counterpart is a Mikrotik 1100AH in the data center. We already run a 450G from the office via multiple uplinks to the data center, so I think I know how to configure it… works fine from there. Now the problem.
So far it is my computer there, which was using Windows PPTP client to hook up to either the PPTP server of the Mikrotik or our firewall server virtual machine (company policy - computers are supposed to go through the firewall). It works perfectly with both, sufing, remote desktop all work perfectly fine.
Because this external location should be always on and not only handle a computer but also other integrated stuff, I need to move it up to a site to site link which is basically a Mikrotik 750. I have established the necesseary elements for a PPTP connection and theoretically it all works fine… just performance sucks as hell. I am not really talking of throughput here, but of stuck connections. RDP turns hardly usable, takes seconds until something happens. It looks like packet loss, or a large packet issue, but it does so… on the same DSL line that I also user otherwise, perfectly fine. It works, so to say, totally good as long as I connect via Windows client, and turns into hell the moment I connect via Mikrotik. I can not even type a text via remote desktop without the connection hanging every couple of entries. Not good - one reason to put the 750 there is to easily hook up voip phones.
The setup:
750:
set default change-tcp-mss=yes name=default only-one=default use-compression=default use-encryption=default use-ipv6=yes
use-mpls=default use-vj-compression=default
set default-encryption change-tcp-mss=yes name=default-encryption only-one=default use-compression=default use-encryption=
yes use-ipv6=yes use-mpls=default use-vj-compression=default
/interface pptp-client
add add-default-route=no allow=pap,chap,mschap1,mschap2 connect-to=xxx dial-on-demand=no disabled=no max-mru=1460
max-mtu=1460 mrru=1614 name=fabric-ff-01 password=xxx profile=default-encryption user=fabric-00-02
This also creates the proper entries to put the MTU to 1460 on the link.
1100AH:
add caller-id=“” disabled=no limit-bytes-in=0 limit-bytes-out=0 local-address=
10.255.255.1 name=fabric-00-02 password=xxx profile=link-encryption
remote-address=10.255.0.2 routes=“” service=any
add disabled=no name=fabric-00-02 user=fabric-00-02
/interface pptp-server server
set authentication=mschap1,mschap2 default-profile=default-encryption enabled=yes
keepalive-timeout=30 max-mru=1460 max-mtu=1460 mrru=disabled
Naturally the 750 goes through another NAT thanks to our DSL provider here (simple integrated box, gives me only a 192.168.0.1 namespace and no way to directly use my own PPPOE link, at least not without serious tinkering on the whole thing). I assume there is some fancy other element wrong, but I can not figure out what.
As a side note - something seems to be REALLY bad with my connection in general. It could be this is the problem. As you can see above, MRU / MTU are aset to 1460. So far so good, but:
ping -l 1440 - times out. Ah? 1440 is not that ig a packet.
ping -l 1430 - 50% packet loss? AH? Sorry? Sometimes it works, but this is not “ok” so to say.
ping -l 1425 - works.
Anyone an idea what to do?