Cisco VPN Client Connects to PIX 501 Without Rule Base?

[RecLambyUK]

Hi there,

I have set up a remote VPN on a Pix 501. It uses an AAA RADIUS server on our internal network and all works fine. To do some testing I removed any access rules/NAT rules etc to see what happened... With all the rules removed I can still establish an IPSEC VPN Connection to our PIX. While removing the rules etc mean that I cannot see anything on the internal network on this connection I would have thought that removing all rules would prevent a connection from even establishing? Can someone clarify this for me? I have removed the Bypass Access check on all IPSEC traffic already so it should be using my rule base. My config is as below....

Thanks for your help, John.

Building configuration...
: Saved
:
PIX Version 6.3(5)
interface ethernet0 auto
interface ethernet1 100full
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password **** encrypted
passwd **** encrypted
hostname wwvpn
domain-name walshwestern.com
fixup protocol dns maximum-length 512
fixup protocol ftp 21
fixup protocol h323 h225 1720
fixup protocol h323 ras 1718-1719
fixup protocol http 80
fixup protocol rsh 514
fixup protocol rtsp 554
fixup protocol sip 5060
fixup protocol sip udp 5060
fixup protocol skinny 2000
fixup protocol smtp 25
fixup protocol sqlnet 1521
fixup protocol tftp 69
names
name 192.168.1.77 LAPTOP
object-group network EXT_ACCESS
network-object 172.20.12.0 255.255.255.0
network-object LAPTOP 255.255.255.255
object-group network hinckley_lan_a
network-object 172.20.4.0 255.255.252.0
network-object 3.1.0.0 255.255.0.0
pager lines 24
mtu outside 1500
mtu inside 1500
ip address outside 192.168.1.100 255.255.255.0
ip address inside 172.20.7.110 255.255.252.0
ip audit info action alarm
ip audit attack action alarm
ip local pool WW_IP_POOL 172.20.12.0-172.20.12.254 mask 255.255.255.0
pdm location 172.20.7.4 255.255.255.255 inside
pdm location 172.20.7.6 255.255.255.255 inside
pdm location 3.1.10.0 255.255.255.0 inside
pdm location 3.1.0.0 255.255.0.0 inside
pdm location LAPTOP 255.255.255.255 outside
pdm location 172.20.12.0 255.255.255.0 outside
pdm group EXT_ACCESS outside
pdm group hinckley_lan_a inside
pdm logging informational 100
pdm history enable
arp timeout 14400
global (outside) 1 interface
route outside 0.0.0.0 0.0.0.0 192.168.1.100 1
route inside 3.1.0.0 255.255.0.0 172.20.7.251 1
timeout xlate 0:05:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h225 1:00:00
timeout h323 0:05:00 mgcp 0:05:00 sip 0:30:00 sip_media 0:02:00
timeout sip-disconnect 0:02:00 sip-invite 0:03:00
timeout uauth 0:05:00 absolute
aaa-server TACACS+ protocol tacacs+
aaa-server TACACS+ max-failed-attempts 3
aaa-server TACACS+ deadtime 10
aaa-server RADIUS protocol radius
aaa-server RADIUS max-failed-attempts 3
aaa-server RADIUS deadtime 0
aaa-server RADIUS (inside) host 172.20.7.6 monkeydust timeout 5
aaa-server LOCAL protocol local
aaa authentication telnet console LOCAL
aaa authorization command LOCAL
http server enable
http 172.20.4.0 255.255.252.0 inside
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
crypto ipsec transform-set ESP-3DES-MD5 esp-3des esp-md5-hmac
crypto ipsec transform-set ESP-AES-256-MD5 esp-aes-256 esp-md5-hmac
crypto dynamic-map outside_dyn_map 20 set transform-set ESP-AES-256-MD5
crypto map outside_map 65535 ipsec-isakmp dynamic outside_dyn_map
crypto map outside_map client authentication RADIUS
crypto map outside_map interface outside
crypto map inside_map interface inside
isakmp enable outside
isakmp policy 20 authentication pre-share
isakmp policy 20 encryption aes
isakmp policy 20 hash md5
isakmp policy 20 group 2
isakmp policy 20 lifetime 86400
vpngroup wwgroup address-pool WW_IP_POOL
vpngroup wwgroup dns-server 172.20.7.4 172.20.7.8
vpngroup wwgroup wins-server 172.20.7.4
vpngroup wwgroup default-domain walshwestern.com
vpngroup wwgroup idle-time 1800
vpngroup wwgroup password ********
telnet 172.20.4.0 255.255.252.0 inside
telnet timeout 5
ssh timeout 5
console timeout 0
dhcpd auto_config outside
username **** password **** encrypted privilege 15
terminal width 80
Cryptochecksum:1698454f0b93987994c37452584d8112
: end
[OK]

 

[Supergrrover]

As long as you still have the following in the config, the connection will be made.
crypto map outside_map interface outside
isakmp enable outside

Now without NAT and ACLs, no traffic will pass but the tunnel will still connect to the interface just not across that boundry.


Brent
Systems Engineer / Consultant
CCNP, CCSP

 

[RecLambyUK]

Thanks Superggrover, I had managed to sort this issue out late on Friday night and it is exactly as you said. In the end I added a list of dynamic IP Peers into the config so only the IP I specify will connect and it works a treat now.

With regards to the issue I was having, would the connection be a security flaw if it was left open even if no traffic was specified to flow? Just curious...

 

[Supergrrover]

Only in the event that there was a bug in the pix os that would allow it to be crashed or compromised via isakmp or ipsec. We would all be in a heap of trouble if that were the case.



Brent
Systems Engineer / Consultant
CCNP, CCSP