VPN stops forwarding traffic on subsequent connections (Cisco 861)

Question

Hello everyone,
I have a very strange problem on 2 (independent) Cisco 861 routers in different places.
They are both configured as easyVPN servers. One uses UDP, the other TCP. VPN clients connect by using Cisco VPN client software. This cannot be changed because the customer expects it this way. Both routers have the same problem:
* the first VPN connection after a reset works fine. Traffic passes through and it is perfectly usable. I can ping the internal network interface on the router side from the client without problems.
* the second connection (and all subsequent ones from different client machines etc.) connects fine, no errors on the client whatsoever (not sure I evaluated all possible debug output on the "server" side). However,  no traffic passes through. Pings do not come back from the 861 anymore through the VPN tunnel.
I already enabled ICMP debugging and saw that pings are actually answered by the 861, but do not reach the client.The same seems to happen to any and all other packets as well.
* If I restart the 861 the very same thing happens: first VPN connection works fine. You disconnect, try another connection from the very same client computer, and it does not work anymore until the next router reset.
I append the configuration for sake of completeness. confidential parts are represented by XXX. Some ACLs are not in use right now; I used them for testing.
Quite frankly, I am out of ideas (and desperate).
Any ideas?
Best Regards
Mike
version 15.0
no service pad
service tcp-keepalives-in
service tcp-keepalives-out
service timestamps debug datetime msec localtime show-timezone
service timestamps log datetime msec localtime show-timezone
service password-encryption
service sequence-numbers
hostname XXX
boot-start-marker
boot-end-marker
logging buffered 51200
logging console critical
enable secret 5 XXX
enable password 7 XXX
aaa new-model
aaa authentication login default local
aaa authentication login ciscocp_vpn_xauth_ml_1 local
aaa authorization exec default local
aaa authorization network ciscocp_vpn_group_ml_1 local
aaa session-id common
memory-size iomem 10
clock timezone Berlin 1
crypto pki trustpoint TP-self-signed-2638506017
enrollment selfsigned
subject-name cn=IOS-Self-Signed-Certificate-2638506017
revocation-check none
rsakeypair TP-self-signed-2638506017
no ip source-route
ip cef
no ip bootp server
ip domain name local
license udi pid CISCO861-K9 sn XXX
archive
log config
  hidekeys
no spanning-tree vlan 1
username root privilege 15 secret 5 XXX
username remote secret 5 XXX
crypto ctcp port 10000
ip tcp synwait-time 10
ip ssh time-out 60
ip ssh authentication-retries 2
crypto isakmp policy 1
encr 3des
authentication pre-share
group 2
crypto isakmp nat keepalive 20
crypto isakmp client configuration group vpn
key XXX
pool SDM_POOL_1
acl 104
netmask 255.255.255.0
crypto isakmp profile ciscocp-ike-profile-1
   match identity group vpn
   client authentication list ciscocp_vpn_xauth_ml_1
   isakmp authorization list ciscocp_vpn_group_ml_1
   client configuration address respond
   client configuration group vpn
   virtual-template 1
crypto ipsec transform-set ESP-3DES-SHA esp-3des esp-sha-hmac
crypto ipsec profile CiscoCP_Profile1
set transform-set ESP-3DES-SHA
set isakmp-profile ciscocp-ike-profile-1
interface Loopback0
ip address 192.168.234.1 255.255.255.0
interface FastEthernet0
interface FastEthernet1
interface FastEthernet2
interface FastEthernet3
interface FastEthernet4
ip address dhcp
no ip redirects
no ip unreachables
no ip proxy-arp
ip flow ingress
duplex auto
speed auto
interface Virtual-Template1 type tunnel
ip unnumbered Loopback0
tunnel mode ipsec ipv4
tunnel protection ipsec profile CiscoCP_Profile1
interface Vlan1
description $ETH-SW-LAUNCH$$INTF-INFO-HWIC 4ESW$
ip address 192.168.233.1 255.255.255.0
no ip redirects
no ip unreachables
no ip proxy-arp
ip flow ingress
ip virtual-reassembly
ip tcp adjust-mss 1452
ip local pool SDM_POOL_1 192.168.234.2 192.168.234.127
ip forward-protocol nd
no ip http server
ip http secure-server
ip http timeout-policy idle 60 life 86400 requests 10000
ip route 10.179.232.0 255.255.255.0 192.168.233.2
ip route 172.16.0.0 255.255.0.0 192.168.233.2
ip access-list log-update threshold 10
logging trap debugging
access-list 1 remark INSIDE_IF=Vlan1
access-list 1 remark CCP_ACL Category=2
access-list 1 permit 192.168.233.0 0.0.0.255
access-list 100 remark XXX
access-list 100 permit ip 192.168.233.0 0.0.0.255 any
access-list 100 permit ip 192.168.234.0 0.0.0.255 any
access-list 101 remark CCP_ACL Category=4
access-list 101 permit ip 192.168.233.0 0.0.0.255 any
access-list 101 permit ip 192.168.234.0 0.0.0.255 any
access-list 102 permit ip 192.168.233.0 0.0.0.255 192.168.234.0 0.0.0.255
access-list 103 permit ip 192.168.233.0 0.0.0.255 192.168.234.0 0.0.0.255 log
access-list 103 permit ip 192.168.234.0 0.0.0.255 192.168.233.0 0.0.0.255 log
access-list 104 permit ip 192.168.233.0 0.0.0.255 any log-input
access-list 104 permit ip 192.168.234.0 0.0.0.255 any log-input
no cdp run
control-plane
banner exec ^CCC
XXX
^C
banner login ^CCC
XXX
^C
line con 0
no modem enable
transport output telnet
line aux 0
transport output telnet
line vty 0 4
privilege level 15
transport input ssh
scheduler max-task-time 5000
scheduler allocate 4000 1000
scheduler interval 500
end

Answer 1

Hi,
I addded a dynamic crypto map to the configuration according to the document you sent. However, it does not work yet.
There must be some stupid mistake or mixup with the old config.
The router logs:
000038: *Mar  1 01:19:24.047 Berlin: %CRYPTO-6-IKMP_MODE_FAILURE: Processing of Aggressive mode failed with peer at XXX
000039: *Mar  1 01:19:29.403 Berlin: CTCP: cTCP connection entry not found. Dropping the packet
Correspondingly, the client retransmits a few times during a connection attempt and then fails.
The current configuration is:
version 15.0
no service pad
service tcp-keepalives-in
service tcp-keepalives-out
service timestamps debug datetime msec localtime show-timezone
service timestamps log datetime msec localtime show-timezone
service password-encryption
service sequence-numbers
hostname XXX
boot-start-marker
boot-end-marker
logging buffered 51200
logging console critical
enable secret XXX
enable password XXX
aaa new-model
aaa authentication login default local
aaa authentication login ciscocp_vpn_xauth_ml_1 local
aaa authorization exec default local
aaa authorization network ciscocp_vpn_group_ml_1 local
aaa session-id common
memory-size iomem 10
clock timezone Berlin 1
crypto pki trustpoint TP-self-signed-2638506017
enrollment selfsigned
subject-name cn=IOS-Self-Signed-Certificate-2638506017
revocation-check none
rsakeypair TP-self-signed-2638506017
no ip source-route
no ip cef
no ip bootp server
ip domain name local
license udi pid CISCO861-K9 sn XXX
archive
log config
  hidekeys
no spanning-tree vlan 1
username root privilege 15 secret 5 XXX
username remote secret 5 XXX
crypto ctcp keepalive 10
crypto ctcp port 10000
ip tcp synwait-time 10
ip ssh time-out 60
ip ssh authentication-retries 2
crypto isakmp policy 1
encr 3des
authentication pre-share
group 2
crypto isakmp nat keepalive 20
crypto isakmp client configuration group vpn
key XXX
pool SDM_POOL_1
acl 105
netmask 255.255.255.0
crypto isakmp client configuration group testgroup
key XXX
pool SDM_POOL_1
crypto isakmp profile ciscocp-ike-profile-1
   match identity group vpn
   client authentication list ciscocp_vpn_xauth_ml_1
   isakmp authorization list ciscocp_vpn_group_ml_1
   client configuration address respond
   client configuration group vpn
crypto isakmp profile VPNclient
   description VPN clients profile
   match identity group testgroup
   client authentication list clientauth
   isakmp authorization list groupauthor
   client configuration address respond
crypto ipsec transform-set ESP-3DES-SHA esp-3des esp-sha-hmac
crypto ipsec profile CiscoCP_Profile1
set transform-set ESP-3DES-SHA
set isakmp-profile ciscocp-ike-profile-1
crypto dynamic-map dynmap 5
set transform-set ESP-3DES-SHA
set isakmp-profile VPNclient
crypto map mymap 10 ipsec-isakmp dynamic dynmap
interface Loopback0
ip address 192.168.234.1 255.255.255.0
interface FastEthernet0
interface FastEthernet1
interface FastEthernet2
interface FastEthernet3
interface FastEthernet4
mtu 1300
ip address dhcp
no ip redirects
no ip unreachables
no ip proxy-arp
ip flow ingress
duplex auto
speed auto
interface Virtual-Template1 type tunnel
ip unnumbered Loopback0
tunnel mode ipsec ipv4
crypto map mymap
interface Vlan1
description $ETH-SW-LAUNCH$$INTF-INFO-HWIC 4ESW$
ip address 192.168.233.1 255.255.255.0
no ip redirects
no ip unreachables
no ip proxy-arp
ip flow ingress
ip virtual-reassembly
ip tcp adjust-mss 1452
ip local pool SDM_POOL_1 192.168.234.2 192.168.234.127
ip forward-protocol nd
no ip http server
ip http secure-server
ip http timeout-policy idle 60 life 86400 requests 10000
ip route 10.179.232.0 255.255.255.0 192.168.233.2
ip route 172.16.0.0 255.255.0.0 192.168.233.2
ip access-list log-update threshold 10
logging trap debugging
access-list 1 remark INSIDE_IF=Vlan1
access-list 1 remark CCP_ACL Category=2
access-list 1 permit 192.168.233.0 0.0.0.255
access-list 100 remark XXX
access-list 100 permit ip 192.168.233.0 0.0.0.255 any
access-list 100 permit ip 192.168.234.0 0.0.0.255 any
access-list 101 remark CCP_ACL Category=4
access-list 101 permit ip 192.168.233.0 0.0.0.255 any
access-list 101 permit ip 192.168.234.0 0.0.0.255 any
access-list 102 permit ip 192.168.233.0 0.0.0.255 192.168.234.0 0.0.0.255
access-list 103 permit ip 192.168.233.0 0.0.0.255 192.168.234.0 0.0.0.255 log
access-list 103 permit ip 192.168.234.0 0.0.0.255 192.168.233.0 0.0.0.255 log
access-list 104 permit ip 192.168.233.0 0.0.0.255 any log-input
access-list 104 permit ip 192.168.234.0 0.0.0.255 any log-input
access-list 105 permit ip 192.168.233.0 0.0.0.255 192.168.234.0 0.0.0.255
no cdp run
control-plane
banner exec ^CCC
XXX
^C
banner login ^CCC
XXX
^C
line con 0
no modem enable
transport output telnet
line aux 0
transport output telnet
line vty 0 4
privilege level 15
transport input ssh
scheduler max-task-time 5000
scheduler allocate 4000 1000
scheduler interval 500
end