Hi all
I was hoping someone would be able to shed some light on my current problem.
Got a Cisco 877W up and running on a PPPoE ADSL2+ connection with my ISP.
Router is set up as proxyDNS and the local workstations are configured to use the router as both gateway and DNS via DHCP.
After a router reboot everything is working as expected, however after 1 to 6 hours DNS resolution from the locally connected workstations (Windows 7 and other devices) stops working. I am fairly confident the problem is with the router (perhaps IOS), because if I change the DHCPs DNS server entries to my ISP DNS it works. If I change DNS to the router IP, resolution eventually fails. In other words:
THIS ALWAYS WORK
ip dhcp pool DHCP_LAN
dns-server 111.118.175.56 (ISP DNS)
THIS WORK FOR A WHILE, BUT EVENTUALLY FAILS
ip dhcp pool DHCP_LAN
dns-server 192.168.50.3 (Router IP)
Troubleshooting examples from Router & Workstation + Router config provided below.
Any feedback is highly appreciated.
RUNNING CONFIGURATION
Current configuration : 4108 bytes
!
version 12.4
no service pad
service tcp-keepalives-in
service tcp-keepalives-out
service timestamps debug uptime
service timestamps log uptime
service password-encryption
service sequence-numbers
!
hostname 877gateway.org
!
boot-start-marker
boot-end-marker
!
no aaa new-model
!
dot11 ssid 877-WiFi
authentication open
authentication key-management wpa
guest-mode
wpa-psk ascii "removed"
!
ip cef
!
no ip dhcp use vrf connected
ip dhcp excluded-address 192.168.50.1 192.168.50.10
!
ip dhcp pool DHCP_LAN
import all
network 192.168.50.0 255.255.255.0
dns-server 192.168.50.3
default-router 192.168.50.3
!
ip dhcp pool QNAP219
host 192.168.50.9 255.255.255.0
client-identifier "removed"
!
ip dhcp pool X58A_N1
host 192.168.50.51 255.255.255.0
client-identifier "removed"
!
ip dhcp pool X58A_N2
host 192.168.50.52 255.255.255.0
client-identifier "removed"
!
ip name-server 111.118.175.56
ip name-server 118.127.33.48
!
multilink bundle-name authenticated
!
username "removed" privilege 15 password "removed"
archive
log config
hidekeys
!
bridge irb
!
interface ATM0
no ip address
ip route-cache flow
no atm ilmi-keepalive
dsl operating-mode auto
!
interface ATM0.1 point-to-point
no snmp trap link-status
pvc 8/35
pppoe-client dial-pool-number 1
!
!
interface FastEthernet0
!
interface FastEthernet1
!
interface FastEthernet2
!
interface FastEthernet3
!
interface Dot11Radio0
no ip address
ip route-cache flow
!
encryption mode ciphers tkip
!
ssid 877-WiFi
!
speed basic-1.0 2.0 5.5 6.0 9.0 11.0 12.0 18.0 24.0 36.0 48.0 54.0
station-role root
no cdp enable
bridge-group 1
bridge-group 1 subscriber-loop-control
bridge-group 1 spanning-disabled
bridge-group 1 block-unknown-source
no bridge-group 1 source-learning
no bridge-group 1 unicast-flooding
!
interface Vlan1
no ip address
ip route-cache flow
bridge-group 1
bridge-group 1 spanning-disabled
!
interface Dialer0
ip address negotiated
ip access-group 101 in
no ip redirects
no ip unreachables
ip mtu 1492
ip nat outside
ip virtual-reassembly
encapsulation ppp
ip route-cache flow
dialer pool 1
dialer-group 1
no cdp enable
ppp pap sent-username "removed" password "removed"
ppp ipcp dns request
ppp ipcp route default
!
interface BVI1
ip address 192.168.50.3 255.255.255.0
ip access-group 102 in
ip nat inside
ip virtual-reassembly
ip route-cache flow
ip tcp adjust-mss 1452
!
ip flow-cache timeout active 1
ip flow-export source Vlan1
ip flow-export version 9
ip flow-export destination 192.168.50.53 2048
!
no ip http server
no ip http secure-server
ip dns server
ip nat inside source list 1 interface Dialer0 overload
!
access-list 1 permit any
access-list 101 permit ip any any
access-list 102 permit ip any any
dialer-list 1 protocol ip permit
snmp-server community public RO
snmp-server ifindex persist
!
control-plane
!
bridge 1 route ip
!
line con 0
exec-timeout 0 0
logging synchronous
no modem enable
line aux 0
line vty 0 4
exec-timeout 0 0
password "removed"
logging synchronous
login local
!
scheduler max-task-time 5000
!
webvpn cef
end
ROUTER TROUBLESHOOTING
Show Version
ROM: System Bootstrap, Version 12.3(8r)YI2, RELEASE SOFTWARE
877gateway.org uptime is 16 hours, 57 minutes
System returned to ROM by reload
System image file is "flash:c870-adventerprisek9-mz.124-15.T.bin"
Cisco 877W (MPC8272) processor (revision 0x200) with 118784K/12288K bytes of memory.
DNS test from router (DNS always working from router)
877gateway.org#ping google.com
Translating "google.com"...domain server (111.118.175.56) [OK]
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 74.125.237.131, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 32/44/60 ms
877gateway.org#tracer google.com
Type escape sequence to abort.
Tracing the route to google.com (74.125.237.131)
1 "removed"
2 "removed"
3 "removed"
4 "removed"
5 202.7.171.46 48 msec 52 msec 28 msec
6 66.249.95.234 36 msec 112 msec 52 msec
7 72.14.237.137 36 msec 28 msec 36 msec
8 google.com (74.125.237.131) 32 msec 48 msec 28 msec
877gateway.org#
WORKSTATION (WIN7) TROUBLESHOOTING
Ethernet adapter "Local Area Connection" on PC
IPv4 Address | : 192.168.50.51(Preferred) |
Subnet Mask | : 255.255.255.0 |
Default Gateway | : 192.168.50.3 |
DHCP Server | : 192.168.50.3 |
DNS Servers | : 192.168.50.3 |
NetBIOS over Tcpip | : Enabled |
DNS troubleshooting from workstation (DNS stops working after a while)
C:\>ping -n 2 google.com
Ping request could not find host google.com. Please check the name and try again
.
C:\>tracert -d google.com
Unable to resolve target system name google.com.
C:\>nslookup
DNS request timed out.
timeout was 2 seconds.
Default Server: UnKnown
Address: 192.168.50.3
> server 192.168.50.3
Default Server: [192.168.50.3]
Address: 192.168.50.3
> google.com
Server: [192.168.50.3]
Address: 192.168.50.3
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
*** Request to [192.168.50.3] timed-out
>
