Cisco Asa PPTP Passthrough

Problem

You cannot open a Microsoft client VPN tunnel with a cisco PIX or ASA in front of you on the network.

Solution

You need the following open (outbound)

  • TCP port 1723 (thats pptp)
  • Protocol 47 (GRE) – note thats a PROTOCOL and NOT a PORT

Allow PPTP Client through the ASA via Command Line

1. Connect to the ASA then add PPTP inspection to the default inspection map.

PetesASA> PetesASA> en Password: ******** PetesASA# conf t PetesASA(config)# policy-map global_policy PetesASA(config)# (config-pmap)# class inspection_default PetesASA(config)# inspect pptp PetesASA(config)# 

2. Then allow the GRE protocol and TCP Port 1723 outbound.

PetesASA(config)# access-list outbound extended permit gre any any PetesASA(config)# access-list outbound extended permit tcp any any eq pptp PetesASA(config)# access-group outbound in interface inside 

3. Save the changes.

PetesASA(config)# write mem Building configuration... Cryptochecksum: 5c8dfc45 ee6496db 8731d2d5 fa945425

8695 bytes copied in 3.670 secs (2898 bytes/sec) [OK] PetesASA(config)#