07-22-2012 02:26 PM - edited 03-11-2019 04:33 PM
Greetings,
I've spent the better part of a week trying to pound this out.
We have a Cisco ASA 5505 (v7.2(3)) with a "fairly" normal configuration yet we have a problem where it appears UDP/53 traffic is denied on our inside network.
here is output from our sys log:
SyslogID Source IP Dest IP Description
305006 172.18.22.3 portmap translation creation failed for udp src inside:172.18.22.156/42013 dst inside:172.18.22.3/53
To give some clarification:
172.18.22.3 is one of our DNS servers
172.18.22.156 is a device we're experimenting with.
We've bypassed the Cisco by using a 4G wireless router with this same device - and it works flawlessly.
Here is a [scrubbed] copy of our config. It is what I inherited from the previous admin - I'm not sure of all its finer points (I'm not Cisco certified -- perhaps I'm just certifiable.)
Any help would be greatly appreciated.
-knme
: Saved
:
ASA Version 7.2(3)
!
hostname [redacted]
domain-name [redacted]
enable password [redacted] encrypted
names
!
interface Vlan1
nameif inside
security-level 100
ip address 172.18.22.6 255.255.255.0
!
interface Vlan2
nameif outside
security-level 0
ip address 999.999.999.999 255.255.255.248
!
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
!
passwd [redacted] encrypted
ftp mode passive
clock timezone EST -5
clock summer-time EDT recurring
dns domain-lookup outside
dns server-group DefaultDNS
name-server 198.6.1.142
name-server 198.6.1.1
domain-name ocm.local
same-security-traffic permit inter-interface
same-security-traffic permit intra-interface
access-list inside_nat0_outbound extended permit ip any 172.18.22.64 255.255.255.240
access-list outside_access_in remark inbound icmp
access-list outside_access_in extended permit icmp any any echo
access-list outside_access_in remark inbound icmp-echo-reply
access-list outside_access_in extended permit icmp any any echo-reply
access-list inside_access_in extended permit tcp any eq domain any eq domain
access-list inside_access_in extended permit udp any eq domain any eq domain
access-list inside_access_in extended permit tcp any any
access-list inside_access_in extended permit udp any any
access-list inside_access_in extended permit icmp any any echo
access-list inside_access_in extended permit icmp any any traceroute
pager lines 24
logging enable
logging asdm informational
mtu inside 1500
mtu outside 1500
ip local pool ABC 172.18.22.70-172.18.22.74 mask 255.255.255.0
icmp unreachable rate-limit 1 burst-size 1
asdm image disk0:/asdm-523.bin
no asdm history enable
arp timeout 14400
nat-control
global (outside) 101 interface
nat (inside) 0 access-list inside_nat0_outbound
nat (inside) 101 172.18.22.0 255.255.255.0
access-group inside_access_in in interface inside
access-group outside_access_in in interface outside
route outside 0.0.0.0 0.0.0.0 65.215.53.161 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 uauth 0:05:00 absolute
aaa-server OCM protocol nt
aaa-server OCM host 172.18.22.2
timeout 5
nt-auth-domain-controller Fileserv
aaa authentication ssh console LOCAL
http server enable
http 172.18.22.0 255.255.255.0 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 dynamic-map outside_dyn_map 20 set pfs
crypto dynamic-map outside_dyn_map 20 set transform-set ESP-3DES-SHA
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
telnet timeout 5
ssh 172.18.22.0 255.255.255.0 inside
ssh timeout 5
console timeout 0
dhcpd auto_config outside
!
!
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
inspect pptp
inspect icmp
inspect http
inspect icmp error
inspect ipsec-pass-thru
!
service-policy global_policy global
ntp server 64.90.182.55 source outside prefer
group-policy ABC internal
group-policy ABC attributes
dns-server value 172.18.22.2 172.18.22.3
vpn-tunnel-protocol IPSec
default-domain value ABC
username admin password [redacted] encrypted privilege 15
tunnel-group ABC type ipsec-ra
tunnel-group ABC general-attributes
address-pool ABC
authentication-server-group ABC
default-group-policy ABC
tunnel-group ABC ipsec-attributes
pre-shared-key *
prompt hostname context
Cryptochecksum:5d3c117cfd8e54a4ba032de9330c51f9
: end
asdm image disk0:/asdm-523.bin
no asdm history enable
07-22-2012 02:49 PM
Without looking at your config: You need to find out why your client .156 sends the packets to the ASA when he wants to reach your internal DNS. As they are both in the same subnet, the ASA shouldn't see that traffic. Start your troubleshooting at the IP-config and routing-config of the client.
07-22-2012 03:51 PM
Hello Karsten,
Thanks for a very prompt response. I do apreciate it.
Sadly I do not have access to the IP-config nor routing-config of the client. They're "black box units". They obtain IP address from our DHCP server - that is pretty much all I know about them.
Any other suggestions?
-knme
07-23-2012 12:58 AM
Are there other clients with that problem? Have you doublechecked the DHCP-Scope?
Sent from Cisco Technical Support iPad App
07-23-2012 06:11 PM
Thanks again Karsten,
No - no other users.
Did discover that when pinging the device the reply is being rejected by the firewall. All are in agreement that this sort of traffic should not be seen at the firewall level so we're really not sure what is going on.
Almost seems like the subnet of the device does not match the subnet of the rest of the network but it is nearly impossible to check b/c the device is not capable.
-knme
07-23-2012 11:55 PM
Are the other clients getting their IP-config also from the same DHCP-server? You can capture the packets that are directly leaving the problematic PC. If the destination-L2-address is the ASA, then the problem is in the client-config.
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