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Cisco VPN Expert Needed - Can't get DHCP to work over VPN (ASA5510/ASA5505)

Posted on 2009-04-02
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Last Modified: 2012-08-14
I need help getting DHCP relay to work on a Cisco VPN. I have a simple network setup. There are two sites:

Main site: Windows SBS 2003 server (providing DHCP services for the network). About 20 client computers. Has Cisco ASA 5510 firewall (see ASA5510 config file below). This network is on the 192.168.1.x address scheme.

Remote site: Has a Cisco ASA 5505, remote printer, and 1 computer. I'd like this computer to get its IP address from the Windows SBS server, so it can be virtually part of the main sites network. I can't get a device from this remote network to pick up an IP over the VPN to the Windows SBS Server, even with DHCP relay enabled on the remote side.

The main and remote site have a site to site VPN setup that is working.

The configs for the units are below (the second config starts around line 213). Any ideas?
ASA5510:
 
: Saved
:
ASA Version 8.0(4) 
!
hostname AdminASA5510
domain-name adminasa.kcfd20.org
enable password * encrypted
passwd * encrypted
names
name 74.94.67.57 Station21
name 192.168.21.0 station21-network
dns-guard
!
interface Ethernet0/0
 description IP: 74.93.110.249-253
 nameif outside
 security-level 1
 ip address 74.93.110.249 255.255.255.248 
!
interface Ethernet0/1
 shutdown
 no nameif
 no security-level
 no ip address
!
interface Ethernet0/2
 nameif Inside
 security-level 15
 ip address 192.168.1.1 255.255.255.0 
!
interface Ethernet0/3
 shutdown
 no nameif
 no security-level
 no ip address
!
interface Management0/0
 nameif management
 security-level 100
 ip address 192.168.2.1 255.255.255.0 
 management-only
!
boot system disk0:/asa804-k8.bin
ftp mode passive
clock timezone PST -8
clock summer-time PDT recurring 1 Sun Apr 2:00 last Sun Oct 2:00
dns domain-lookup outside
dns server-group DefaultDNS
 name-server 208.67.222.222
 name-server 208.67.220.220
 name-server 68.87.69.146
 domain-name adminasa.kcfd20.org
access-list inside_access_in extended permit ip any any 
access-list inbound extended permit tcp any host 74.93.110.250 eq 9100 
access-list inbound extended permit tcp any interface outside eq www 
access-list inbound extended permit tcp any interface outside eq https 
access-list inbound extended permit tcp any interface outside eq 4125 
access-list inbound extended permit tcp any interface outside eq 3389 
access-list inbound extended permit udp any host 192.168.1.10 eq domain 
access-list inbound extended permit tcp any interface outside eq smtp 
access-list inbound extended permit tcp any interface outside eq pop3 
access-list inbound extended permit tcp any interface outside eq ftp 
access-list inbound extended permit tcp any interface outside eq imap4 
access-list outside_access_out extended permit ip interface outside any 
access-list management_nat0_outbound extended permit ip any 192.168.1.192 255.255.255.192 
access-list management_nat0_outbound extended permit ip 192.168.1.0 255.255.255.0 host Station21 
access-list management_nat0_outbound extended permit ip station21-network 255.255.255.0 192.168.1.0 255.255.255.0 
access-list vpn_splitTunnelAcl standard permit any 
access-list no-nat extended permit ip 192.168.1.0 255.255.255.0 station21-network 255.255.255.0 
access-list Inside_cryptomap extended permit ip 192.168.1.0 255.255.255.0 station21-network 255.255.255.0 
access-list Inside_cryptomap extended permit ip host 192.168.1.10 host Station21 
pager lines 24
logging enable
logging buffer-size 8192
logging asdm informational
mtu outside 1500
mtu Inside 1500
mtu management 1500
ip local pool VPNIPs 192.168.1.220-192.168.1.230 mask 255.255.255.0
no failover
icmp unreachable rate-limit 1 burst-size 1
asdm image disk0:/asdm-61551.bin
no asdm history enable
arp timeout 14400
global (outside) 1 interface
nat (Inside) 0 access-list no-nat
nat (Inside) 1 0.0.0.0 0.0.0.0
nat (management) 0 access-list management_nat0_outbound
static (Inside,outside) tcp interface www 192.168.1.10 www netmask 255.255.255.255  dns 
static (Inside,outside) tcp interface https 192.168.1.10 https netmask 255.255.255.255  dns 
static (Inside,outside) tcp interface smtp 192.168.1.10 smtp netmask 255.255.255.255  dns 
static (Inside,outside) tcp interface 4125 192.168.1.10 4125 netmask 255.255.255.255  dns 
static (Inside,outside) tcp interface pop3 192.168.1.10 pop3 netmask 255.255.255.255  dns 
static (Inside,outside) tcp interface ftp 192.168.1.10 ftp netmask 255.255.255.255  dns 
static (Inside,outside) tcp interface imap4 192.168.1.10 imap4 netmask 255.255.255.255  dns 
static (Inside,outside) udp interface dnsix 192.168.1.10 dnsix netmask 255.255.255.255 
static (Inside,outside) tcp interface 3389 192.168.1.10 3389 netmask 255.255.255.255  dns 
access-group inbound in interface outside
route outside 0.0.0.0 0.0.0.0 74.93.110.254 1
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 icmp 0:00:02
timeout sunrpc 0:10:00 h323 0:05:00 h225 1:00:00 mgcp 0:05:00 mgcp-pat 0:05:00
timeout sip 0:30:00 sip_media 0:02:00 sip-invite 0:03:00 sip-disconnect 0:02:00
timeout sip-provisional-media 0:02:00 uauth 0:05:00 absolute
dynamic-access-policy-record DfltAccessPolicy
http server enable
http 192.168.2.0 255.255.255.0 management
http 192.168.1.0 255.255.255.0 Inside
http 192.168.0.0 255.255.255.0 Inside
no snmp-server location
no snmp-server contact
snmp-server enable traps snmp authentication linkup linkdown coldstart
crypto ipsec transform-set ESP-3DES-SHA esp-3des esp-sha-hmac 
crypto ipsec transform-set ESP-AES-256-MD5 esp-aes-256 esp-md5-hmac 
crypto ipsec transform-set ESP-DES-SHA esp-des esp-sha-hmac 
crypto ipsec transform-set ESP-DES-MD5 esp-des esp-md5-hmac 
crypto ipsec transform-set ESP-AES-192-MD5 esp-aes-192 esp-md5-hmac 
crypto ipsec transform-set ESP-3DES-MD5 esp-3des esp-md5-hmac 
crypto ipsec transform-set ESP-AES-256-SHA esp-aes-256 esp-sha-hmac 
crypto ipsec transform-set ESP-AES-128-SHA esp-aes esp-sha-hmac 
crypto ipsec transform-set ESP-AES-192-SHA esp-aes-192 esp-sha-hmac 
crypto ipsec transform-set ESP-AES-128-MD5 esp-aes esp-md5-hmac 
crypto ipsec security-association lifetime seconds 28800
crypto ipsec security-association lifetime kilobytes 4608000
crypto dynamic-map outside_dyn_map 20 set pfs group1
crypto dynamic-map outside_dyn_map 20 set transform-set ESP-3DES-SHA
crypto dynamic-map outside_dyn_map 20 set security-association lifetime seconds 28800
crypto dynamic-map outside_dyn_map 20 set security-association lifetime kilobytes 4608000
crypto dynamic-map outside_dyn_map 40 set pfs group1
crypto dynamic-map outside_dyn_map 40 set transform-set ESP-3DES-SHA
crypto dynamic-map outside_dyn_map 40 set security-association lifetime seconds 28800
crypto dynamic-map outside_dyn_map 40 set security-association lifetime kilobytes 4608000
crypto dynamic-map outside_dyn_map 60 set pfs group1
crypto dynamic-map outside_dyn_map 60 set transform-set ESP-3DES-SHA
crypto dynamic-map outside_dyn_map 60 set security-association lifetime seconds 28800
crypto dynamic-map outside_dyn_map 60 set security-association lifetime kilobytes 4608000
crypto map outside_map 10 match address Inside_cryptomap
crypto map outside_map 10 set peer Station21 
crypto map outside_map 10 set transform-set ESP-AES-256-SHA
crypto map outside_map 10 set security-association lifetime seconds 28800
crypto map outside_map 10 set security-association lifetime kilobytes 4608000
crypto map outside_map 65535 ipsec-isakmp dynamic outside_dyn_map
crypto map outside_map interface outside
crypto isakmp enable outside
crypto isakmp policy 10
 authentication pre-share
 encryption 3des
 hash sha
 group 2
 lifetime 86400
no crypto isakmp nat-traversal
telnet 192.168.1.10 255.255.255.255 Inside
telnet timeout 5
ssh timeout 5
console timeout 0
management-access management
threat-detection basic-threat
threat-detection statistics port
threat-detection statistics protocol
threat-detection statistics access-list
no threat-detection statistics tcp-intercept
webvpn
 enable outside
group-policy vpn_1 internal
group-policy vpn_1 attributes
 wins-server value 192.168.1.10
 dns-server value 192.168.1.10
 vpn-tunnel-protocol IPSec 
 split-tunnel-policy tunnelspecified
 split-tunnel-network-list value vpn_splitTunnelAcl
username * password * encrypted privilege 14
username * password * encrypted
tunnel-group 74.94.67.57 type ipsec-l2l
tunnel-group 74.94.67.57 ipsec-attributes
 pre-shared-key *
!
class-map inspection_default
 match default-inspection-traffic
!
!
policy-map type inspect dns migrated_dns_map_1
 parameters
  message-length maximum 512
policy-map global_policy
 class inspection_default
  inspect dns migrated_dns_map_1 
  inspect ftp 
  inspect h323 h225 
  inspect h323 ras 
  inspect rsh 
  inspect rtsp 
  inspect esmtp 
  inspect sqlnet 
  inspect skinny  
  inspect sunrpc 
  inspect xdmcp 
  inspect sip  
  inspect netbios 
  inspect tftp 
!
service-policy global_policy global
smtp-server 192.168.1.10
prompt hostname context 
Cryptochecksum:*
: end
asdm image disk0:/asdm-61551.bin
asdm location 74.93.110.249 255.255.255.255 outside
asdm location 74.93.110.250 255.255.255.255 Inside
asdm location 192.168.1.10 255.255.255.255 Inside
asdm location Station21 255.255.255.255 management
asdm location station21-network 255.255.255.0 management
no asdm history enable
 
ASA5505
 
: Saved
:
ASA Version 8.0(4) 
!
hostname st21asa5505
domain-name station21.kcfd20.org
enable password * encrypted
passwd * encrypted
names
name 192.168.21.0 inside-network
name 192.168.21.40 station-printer
name 74.93.110.249 Admin_Building
!
interface Vlan1
 nameif inside
 security-level 100
 ip address 192.168.21.1 255.255.255.0 
!
interface Vlan2
 nameif outside
 security-level 0
 ip address 74.94.67.57 255.255.255.252 
!
interface Ethernet0/0
 switchport access vlan 2
!
interface Ethernet0/1
!
interface Ethernet0/2
!
interface Ethernet0/3
!
interface Ethernet0/4
!
interface Ethernet0/5
!
interface Ethernet0/6
!
interface Ethernet0/7
!
banner motd Message of the Day!
boot system disk0:/asa804-k8.bin
ftp mode passive
clock timezone PST -8
clock summer-time PDT recurring
dns domain-lookup inside
dns server-group DefaultDNS
 name-server 208.67.220.220
 name-server 208.67.222.222
 domain-name station21.kcfd20.org
access-list inside_access_in extended permit ip any any 
access-list inbound extended permit tcp any interface outside eq 9100 
access-list inbound extended permit tcp any interface outside eq www 
access-list inbound extended permit tcp any interface outside eq https 
access-list no-nat extended permit ip inside-network 255.255.255.0 192.168.1.0 255.255.255.0 
access-list 5510 extended permit ip inside-network 255.255.255.0 192.168.1.0 255.255.255.0 
access-list inside_cryptomap extended permit ip inside-network 255.255.255.0 192.168.1.0 255.255.255.0 
access-list inside_cryptomap extended permit ip host 74.94.67.57 host 192.168.1.10 
pager lines 24
logging enable
logging asdm informational
mtu inside 1500
mtu outside 1500
icmp unreachable rate-limit 1 burst-size 1
asdm image disk0:/asdm-61551.bin
no asdm history enable
arp timeout 14400
global (outside) 1 interface
nat (inside) 0 access-list no-nat
nat (inside) 1 0.0.0.0 0.0.0.0
static (inside,outside) tcp interface www station-printer www netmask 255.255.255.255  dns 
static (inside,outside) tcp interface 9100 station-printer 9100 netmask 255.255.255.255  dns 
access-group inside_access_in in interface inside
access-group inbound in interface outside
route outside 0.0.0.0 0.0.0.0 74.94.67.58 1
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 icmp 0:00:02
timeout sunrpc 0:10:00 h323 0:05:00 h225 1:00:00 mgcp 0:05:00 mgcp-pat 0:05:00
timeout sip 0:30:00 sip_media 0:02:00 sip-invite 0:03:00 sip-disconnect 0:02:00
timeout sip-provisional-media 0:02:00 uauth 0:05:00 absolute
dynamic-access-policy-record DfltAccessPolicy
http server enable
http inside-network 255.255.255.0 inside
http 74.93.110.0 255.255.255.0 outside
no snmp-server location
no snmp-server contact
snmp-server enable traps snmp authentication linkup linkdown coldstart
crypto ipsec transform-set ESP-3DES-SHA esp-3des esp-sha-hmac 
crypto ipsec transform-set ESP-AES-256-MD5 esp-aes-256 esp-md5-hmac 
crypto ipsec transform-set ESP-DES-SHA esp-des esp-sha-hmac 
crypto ipsec transform-set ESP-DES-MD5 esp-des esp-md5-hmac 
crypto ipsec transform-set ESP-AES-192-MD5 esp-aes-192 esp-md5-hmac 
crypto ipsec transform-set ESP-3DES-MD5 esp-3des esp-md5-hmac 
crypto ipsec transform-set ESP-AES-256-SHA esp-aes-256 esp-sha-hmac 
crypto ipsec transform-set ESP-AES-128-SHA esp-aes esp-sha-hmac 
crypto ipsec transform-set ESP-AES-192-SHA esp-aes-192 esp-sha-hmac 
crypto ipsec transform-set ESP-AES-128-MD5 esp-aes esp-md5-hmac 
crypto ipsec security-association lifetime seconds 28800
crypto ipsec security-association lifetime kilobytes 4608000
crypto map outside_map 1 match address 5510
crypto map outside_map 1 set peer Admin_Building 
crypto map outside_map 1 set transform-set ESP-AES-256-SHA
crypto map outside_map 1 set security-association lifetime seconds 28800
crypto map outside_map 1 set security-association lifetime kilobytes 4608000
crypto map outside_map interface outside
crypto isakmp enable outside
crypto isakmp policy 10
 authentication pre-share
 encryption 3des
 hash sha
 group 2
 lifetime 86400
no crypto isakmp nat-traversal
telnet inside-network 255.255.255.0 inside
telnet 192.168.1.0 255.255.255.0 inside
telnet timeout 5
ssh timeout 5
console timeout 0
management-access inside
dhcpd dns 208.67.220.220 208.67.222.222
!
dhcpd address 192.168.21.50-192.168.21.60 inside
dhcpd dns 208.67.220.220 192.168.1.10 interface inside
!
dhcprelay server 192.168.1.10 outside
dhcprelay enable inside
dhcprelay setroute inside
dhcprelay timeout 90
 
threat-detection basic-threat
threat-detection statistics access-list
no threat-detection statistics tcp-intercept
username * password * encrypted
username * password * encrypted
tunnel-group 74.93.110.249 type ipsec-l2l
tunnel-group 74.93.110.249 ipsec-attributes
 pre-shared-key *
!
class-map inspection_default
 match default-inspection-traffic
!
!
policy-map type inspect dns preset_dns_map
 parameters
  message-length maximum 512
policy-map global_policy
 class inspection_default
  inspect dns preset_dns_map 
  inspect ftp 
  inspect h323 h225 
  inspect h323 ras 
  inspect rsh 
  inspect rtsp 
  inspect esmtp 
  inspect sqlnet 
  inspect skinny  
  inspect sunrpc 
  inspect xdmcp 
  inspect sip  
  inspect netbios 
  inspect tftp 
!
service-policy global_policy global
smtp-server 192.168.1.10
prompt hostname context 
Cryptochecksum:*
: end
asdm image disk0:/asdm-61551.bin
asdm location Admin_Building 255.255.255.255 inside
no asdm history enable

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Question by:ssittig
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12 Comments
 
LVL 43

Accepted Solution

by:
JFrederick29 earned 800 total points
ID: 24052606
Add this on the remote 5505:

conf t
access-list 5510 extended permit ip host 74.94.67.57 host 192.168.1.10
0
 
LVL 1

Author Comment

by:ssittig
ID: 24052673
I'll give that a try. I should have results in about 20 minutes. Thank you.
0
 
LVL 33

Assisted Solution

by:MikeKane
MikeKane earned 400 total points
ID: 24052681
Dhcprelay uses the outside address of the firewall as the source address. You have to add the outside address to the interesting traffic ACL (match address) as well as the nonat

access-list no-nat permit IP <outside_address> <dhcpserver_ip>
access-list crypto_map_acl permit IP <outside_address> <dhcpserver_ip>


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LVL 29

Assisted Solution

by:Michael Worsham
Michael Worsham earned 800 total points
ID: 24052761
After a quick read of your config, DHCP Relay cannot be enabled if the ASA is also a DHCP server as well.

The following restrictions apply to the use of the DHCP relay agent:
" The relay agent accepts and responds to client requests on any interface.
" The relay agent cannot be enabled if the ASA/PIX DHCP server is enabled.
" The relay agent will forward requests if IPSec is configured. VPN negotiations will be initiated if a tunnel does not exist.
" Clients must be directly connected to the ASA/PIX and cannot send requests through another relay agent or a router.
" DHCP relay will not work in client mode.

---

dhcprelay server <dhcp_server_ip> <server_ifc>

Replace <dhcp_server_ip> with the IP address of the DHCP server. Replace <server_ifc> with the interface connected to the DHCP server. You can use this command to identify up to four servers.
0
 
LVL 1

Author Comment

by:ssittig
ID: 24052860
MikeKane:  I'll look into that. Thank you.

MWEComputers: I cleared all of the DHCPD lines (337-340 in the config), although the ASDM showed the DHCP server as not enabled, just the configuration information from when it was. I'll give it a go, thanks.
0
 
LVL 1

Author Comment

by:ssittig
ID: 24054189
JFrederick29 - No dice.....

MikeKane: I'll give that a try.....

MWE Computers: Here is what I get on the remote unit when I query the DHCP Relay state:

st21asa5505(config)# show dhcprelay state
Context  Configured as DHCP Relay
Interface inside, Configured for DHCP RELAY SERVER
Interface outside, Configured for DHCP RELAY
st21asa5505(config)#
0
 
LVL 29

Expert Comment

by:Michael Worsham
ID: 24054283
On the SBS server, are you using ISA as well or not?
0
 
LVL 29

Expert Comment

by:Michael Worsham
ID: 24054299
What result do you get if you do 'show dhcprelay statistics'?
0
 
LVL 43

Expert Comment

by:JFrederick29
ID: 24055316
A DHCP scope for the 192.168.21.0/24 subnet exists on the DHCP server, right?
0
 
LVL 43

Expert Comment

by:JFrederick29
ID: 24055332
Try this instead:

On the 5510:

conf t
no access-list Inside_cryptomap extended permit ip host 192.168.1.10 host Station21
access-list Inside_cryptomap extended permit udp host 192.168.1.10 eq bootps host Station21

On the 5505:

conf t
no access-list 5510 extended permit ip host 74.94.67.57 host 192.168.1.10
access-list 5510 extended permit udp host 74.94.67.57 host 192.168.1.10 eq bootps

Also, as I just posted, make sure a scope exists for the 192.168.21.0/24 subnet on the DHCP server.
0
 
LVL 1

Author Comment

by:ssittig
ID: 24055725
Thanks, I'll give that a try on Saturday.
0
 
LVL 1

Author Closing Comment

by:ssittig
ID: 31565911
I ended up using alternate solution (using the router as the DHCP server and using the main site for DNS server info). Thanks for staying with it.
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