Another PIX 501 with VPN problem 1

[bpinter]

Hi, I am trying to configure a PIX 501 for simple PPTP VPN access so that there would be no need to use anything other than the standard Windows Built-in VPN Client. I am a Cisco newbie so I have been using the cisco website and documentation. I think I have done everything they suggested but must be missing something. When I try to connect using Windows VPN I get Error 800 (Win XP) or Error 651 (Win 2K). I have an ADSL connection with static IP and internal mail server.

Configuration of PIX:

Gateway IP: 203.x.x.93
PIX IP External: 203.x.x.94
PIX IP Internal: 192.168.10.100
Server IP: 192.168.10.1

PIX Version 6.1(3)
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password ********** encrypted
passwd ********** encrypted
hostname pixfirewall
domain-name ciscopix.com
fixup protocol ftp 21
fixup protocol http 80
fixup protocol h323 1720
fixup protocol rsh 514
fixup protocol rtsp 554
fixup protocol smtp 25
fixup protocol sqlnet 1521
fixup protocol sip 5060
fixup protocol skinny 2000
names
name 192.168.10.1 mailserver
access-list acl_out permit icmp any any
access-list acl_out permit tcp any host 203.x.x.94 eq smtp
access-list acl_out permit tcp any host 203.x.x.94 eq ident
access-list inside_access_in permit ip any any
access-list 101 permit ip 192.168.10.0 255.255.255.0 192.168.11.0 255.255.255.0
pager lines 24
interface ethernet0 10baset
interface ethernet1 10full
mtu outside 1500
mtu inside 1500
ip address outside 203.x.x.94 255.255.255.0
ip address inside 192.168.10.100 255.255.255.0
ip audit info action alarm
ip audit attack action alarm
ip local pool pptp-pool 192.168.11.11-192.168.11.50
pdm location 203.213.111.94 255.255.255.255 inside
pdm location mailserver 255.255.255.255 inside
pdm logging informational 100
pdm history enable
arp timeout 14400
global (outside) 1 interface
nat (inside) 0 access-list 101
nat (inside) 1 192.168.10.0 255.255.255.0 0 0
static (inside,outside) 203.213.111.94 mailserver netmask 255.255.255.255 0 0
access-group acl_out in interface outside
access-group inside_access_in in interface inside
route outside 0.0.0.0 0.0.0.0 203.213.111.93 1
timeout xlate 0:05:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h323 0:05:00 sip 0:30:00 sip_media 0:02:00
timeout uauth 0:05:00 absolute
aaa-server TACACS+ protocol tacacs+
aaa-server RADIUS protocol radius
http server enable
http 192.168.10.0 255.255.255.0 inside
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
no floodguard enable
sysopt connection permit-pptp
no sysopt route dnat
telnet timeout 5
ssh timeout 5
vpdn group 1 accept dialin pptp
vpdn group 1 ppp authentication pap
vpdn group 1 ppp authentication chap
vpdn group 1 ppp authentication mschap
vpdn group 1 ppp encryption mppe auto
vpdn group 1 client configuration address local pptp-pool
vpdn group 1 pptp echo 60
vpdn group 1 client authentication local
vpdn username cisco password cisco
vpdn enable outside
terminal width 80
Cryptochecksum:d959cc6875adb61ea434e161d39519e1

 

[iiiiss]

Try with debbuging on the PIX eg: "debug cry ips" and "debu cry isa" and send the results

 

[yizhar]

HI.

What is the error message you get on the workstation?
(we don't know all the MS error codes by heart..)
And what messages do you get at the client before the error - can you see this "verifying username and password"?

The correct debug commands at the pix are:
debug ppp ...
debug vpdn ...

http://www.cisco.com/univercd/cc/td/doc/product/iaabu/pix/pix_61/cmd_ref/df.htm#xtocid1

Type show version at the pix.
Do you have DES, 3DES, both or none enabled?
The default DES license will give you MPPE 40 bit encryption (only).

You must use MSCHAP if you wish to use MPPE encryption, so remove the PAP and CHAP statements:
no vpdn group 1 ppp authentication pap
no vpdn group 1 ppp authentication chap

> vpdn group 1 ppp encryption mppe auto
Try the following command instead:
vpdn group 1 ppp encryption mppe 40 required

Try to connect a workstation directly to the pix outside network - does it work now?

Try syslog messages in addition to debug - do you get anything related to the problem?

Look for authentication errors and check the client configuration also - not only the pix.

Bye
Yizhar Hurwitz

http://come.to/yizhar

http://teachers.sivan.co.il/yizhar

 

[bpinter]

Yizhar,

Thanks for your helpful suggestions. I will try the debug options you suggested. This might be a silly question, but does the debug output just appear on the console or do I have to do anything else to view the results of the debug?

The error on the client is "Error 800: Unable to establish the VPN connection. The VPN server may be unreachable, or security parameters may not be configured properly for this connection." I've checked the MS Knowledgebase and they say to contact the manufacturer of the router for an updated firmware if the firmware is dated 2000 or earlier. Mine is Feb 2002 so I didn't update the firmware. When I am trying to connect, it just says "Connecting to 203.x.x.94" and then times out with the error 800.

I have both DES and 3DES on the PIX.

I will post the results of the debug once I've got them.

Thanks again.

 

[bpinter]

Ok, so I tried all the debug options and there are absolutely no debug messages for vpdn or ppp.

I tried to connect the workstation directly to the PIX outside interface, but still unable to connect. Syslog logging was not on, so nothing there either.

About the only thing that I did get was a debug message when I enabled packet debugging on the external interface and here is the output. Not sure what it all means though.

-- IP --
144.x.x.x ==> 203.x.x.94

ver = 0x4 hlen = 0x5 tos = 0x0 tlen = 0x30
id = 0x5f41 flags = 0x40 frag off=0x0
ttl = 0x72 proto=0x6 chksum = 0x529e

-- TCP --
source port = 0x115d dest port = 0x17syn

seq = 0xf0f7c03c
ack = 0x0
hlen = 0x7 window = 0x2238
checksum = 0x4756 urg = 0x0
tcp options: 0x2 0x4 0x5 0xb4
0x1 0x1 0x4 0x2
--------- END OF PACKET ---------

I am guessing (could be way off) that either:

a) the static nat for the mailserver is interfering (is it possible that the VPN is trying to go through to my mailserver?) or

b) the PIX is blocking the packets?

Is there any way to debug the access permissions? Although I remember reading that "vpdn enable outside" gets past the access-lists. Any suggestions much appreciated - I am desperate.

ps. could it make any difference if I tried to use a Cisco VPN client instead of the MS client? If so, where would I get the Cisco client and what config changes do I need to make?

 

[yizhar]

HI.

> ip address outside 203.x.x.94 255.255.255.0
> static (inside,outside) 203.213.111.94 mailserver
> a) the static nat for the mailserver is interfering
Yes - this is probably it.
You must not overlap the addresses.
Best solution - use different ip for mail server and pix interface.
Second best (if you don't have enough addresses): use STATIC TCP (port forward) instead of STATIC, to map only port 25.

> ... do I have to do anything else to view the results of the debug
To see the debug output, it is recommended to open a TELNET session (faster then serial), and issue the command:
terminal monitor

Use only a single session (either TELNET or CONSOLE) so it won't confuse you too much.

> Syslog logging was not on, so nothing there either
So, enable logging.

> ... I tried to use a Cisco VPN client instead ...
It will only work if you configure for IPSEC at the pix. The Cisco VPN client is NOT a PPTP client.


Bye
Yizhar Hurwitz

http://come.to/yizhar

http://teachers.sivan.co.il/yizhar