Cisco 891 PPTP

Hoping someone here can take a look at this config and maybe point me in the right direction.

​

I have a client that used to have an internal IT person. I use that term loosely cause this is a non-profit and this person was not IT, but handled all their IT

​

I have inherited this mess of a network. Cisco 891 is router/firewall front end. There are numerous internal networks, none of which are VLAN'd, all use layer 3 switches with various interfaces programmed with specific IP's in various subnets... just about every switch is throwing VLAN tagging mismatch errors, but hey it works they say! Not sure why it was setup in this fashion, but here I am with it.

​

I know ideally with the state of this network we need to burn it to the ground and start over, but again, client is a non-profit and has very little in the way of funds to put toward a network overhaul.

​

Config here - https://justpaste.it/4osoc

​

Config has been sanitized with various names/IP related info removed, but should be usable for the most part. Looks like half of this config was done with the CCP software while the other half is a hodge-podge of scattered changes.

​

Client wants PPTP VPN. Insists on using it, has internal AD server, wants to use AD auth, etc. etc.. Completely against having to install any software whatsoever.

​

I have PPTP forwarded without issue, seems my problem is actually getting GRE to passthrough. When attempting to connect, it hits, verifies credentials, then just hangs, and subsequently dies. Tried various things, using the built-in SDM_GRE on the 891 and getting an ACL applied that is "permit gre any any", but that ended with the same result and didn't work.

​

Ordinarily I could work my way through this one, but the mess of a config is making me cross-eyed and I seem to keep running into dead ends with nothing working as it should.

​

Thanks in advance for anyone able to offer any input, it is appreciated.