Here is a config from one of my 804 routers that may be of help to you:
!
service timestamps debug uptime
service timestamps log uptime
service password-encryption
no service tcp-small-servers
no service udp-small-servers
!
hostname sd-804-01
!
enable secret xyz
!
no ip name-server
!
isdn switch-type basic-ni1
pots country US
!
ip subnet-zero
no ip domain-lookup
ip routing
!
interface Dialer 1
description connected to Internet
ip address negotiated
ip nat outside
no ip split-horizon
encapsulation ppp
dialer in-band
dialer idle-timeout 120
dialer string 1112223344
dialer hold-queue 10
dialer-group 1
ppp authentication chap pap callin
ppp chap hostname username
ppp chap password xyz
ppp pap sent-username username password xyz
no ppp multilink
no cdp enable
!
interface Ethernet 0
no shutdown
description connected to EthernetLAN
ip address 10.20.1.1 255.255.255.0
ip nat inside
keepalive 10
!
interface BRI 0
no shutdown
description connected to Internet
no ip address
dialer rotary-group 1
isdn spid1 11122233330101
isdn spid2 11122233340101
!
! Access Control List 1
!
no access-list 1
access-list 1 permit 10.20.1.0 0.0.0.255
!
! Dialer Control List 1
!
no dialer-list 1
dialer-list 1 protocol ip permit
!
! Dynamic NAT
!
ip nat translation timeout 86400
ip nat translation tcp-timeout 86400
ip nat translation udp-timeout 300
ip nat translation dns-timeout 60
ip nat translation finrst-timeout 60
ip nat inside source list 1 interface Dialer 1 overload
!
! DHCP Server
!
service dhcp
ip dhcp excluded-address 10.20.1.1 10.20.1.9
ip dhcp pool 1
network 10.20.1.0 255.255.255.0
default-router 10.20.1.1
dns-server 1.2.3.4 1.2.3.5
!
router rip
version 2
network 10.0.0.0
passive-interface Dialer 1
no auto-summary
!
!
ip classless
!
! IP Static Routes
ip route 0.0.0.0 0.0.0.0 Dialer 1
no ip http server
!
end
