here is a simple basic config that might help you, just remember you will have to change it a little for your 2600. This will work on 1700 directly. Also this is used for connecitons over dsl, cable and so forth, private lines would be the tunnel source if you are using them.
!
crypto isakmp policy 25
encr 3des
hash md5
authentication pre-share
crypto isakmp key address destination host ! ISAKmp
!
!
crypto ipsec transform-set ANES esp-3des esp-md5-hmac
mode transport
!
crypto map GRE 50 ipsec-isakmp
description Tunnel to destination host
set peer destination host ip
set transform-set ANES
match address -GRE
!
!
!
interface Loopback0
description Connectionless IP Circuit for
ip address 255.255.255.252
!
interface Tunnel0
description GRE Tunnel to destination Tunnel # from
bandwidth 1024
ip address 255.255.255.252
ip mtu 1440
ip hello-interval eigrp 1 4
ip hold-time eigrp 1 10
ip route-cache flow
no ip route-cache
no ip mroute-cache
tunnel source Ethernet 0
tunnel destination
crypto map GRE
!
!
!
interface Ethernet0
description Public Network Interface to NOC # Acct. #
ip address
no ip directed-broadcast
ip access-group 115 in
no shutdown
crypto map GRE
!
!
interface FastEthernet0
description Protected Network
ip address
no ip directed-broadcast
no shutdown
!
!
!
ip route 255.255.255.255 ! ISP's ,
ip route 255.255.255.255 ! ISP's ,
!
!
access-list 3 remark Telnet Access to VTY's
access-list 3 permit ! Local ,
access-list 3 permit
!
!
!
ip access-list extended GRE
remark Encrypt GRE Traffic from Remote Site to host site
permit gre host destination host ip ! of Ethernet 0
!
!
!
access-list 115 remark Permits and Established from the Internet
access-list 115 permit icmp any host unreachable ! IP Address of Public Interface
access-list 115 permit icmp any host echo-reply ! IP Address of Public Interface
access-list 115 permit icmp any host packet-too-big ! IP Address of Public Interface
access-list 115 permit icmp any host time-exceeded ! IP Address of Public Interface
access-list 115 permit icmp any host traceroute ! IP Address of Public Interface
access-list 115 permit icmp any host administratively-prohibited ! IP Address of Public Interface
access-list 115 permit icmp any host echo ! IP Address of Public Interface
access-list 115 permit tcp host destination host eq telnet ! IP Address of Public Interface
access-list 115 permit udp host destination host host eq isakmp ! IP Address of Public Interface
access-list 115 permit gre host destination host host ! IP Address of Public Interface
access-list 115 permit esp host destination host host ! IP Address of Public Interface
access-list 115 deny ip 127.0.0.0 0.255.255.255 any
access-list 115 deny ip any any
