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Johnny SSH


[Config] DynDNS Update interval question


I am trying to install DynDNS in a Cisco router. The config of the router is fine and the system is up and running.

I would like to make sure that my DynDNS config is fine as I've never dealt with it before and additionally I would like to know what the update interval should be...?

This is the DynDNS config currently:

ip ddns update method <name>
  add http://<uname>:<password>@members.dyndns.org/nic/update?system=dyndns&hostname=<h>&myip=<a>
 interval maximum 28 0 0 0
 interval minimum 0 12 0 0

Additionally is the DDNS string correct too??

I have seen this system update previously while running:

sh log

and all ACLs etc... have been set to 'allow' the service.

Can anybody assist me or suggest anything to be able to be sure that the system is working properly?

I did run

debug ddns ....

and monitored the output of the console on the vty session I was running however, I did not see any output?


This help at all?

What device and version of IOS is being run?


Johnny SSH

It's an 877, here's the sh ver:

Cisco IOS Software, C870 Software (C870-ADVSECURITYK9-M), Version 12.4(15)T13, RELEASE SOFTWARE (fc3)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Wed 07-Apr-10 19:07 by prod_rel_team
ROM: System Bootstrap, Version 12.3(8r)YI4, RELEASE SOFTWARE
IS126 uptime is 6 days, 4 hours, 49 minutes
System returned to ROM by power-on
System restarted at 08:53:58 UTC Fri May 11 2012
System image file is "flash:c870-advsecurityk9-mz.124-15.T13.bin"
This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.
A summary of U.S. laws governing Cisco cryptographic products may be found at:
If you require further assistance please contact us by sending email to
Cisco 877-M (MPC8272) processor (revision 0x400) with 118784K/12288K bytes of memory.
Processor board ID FCZ14339080
MPC8272 CPU Rev: Part Number 0xC, Mask Number 0x10
4 FastEthernet interfaces
1 ATM interface
128K bytes of non-volatile configuration memory.
24576K bytes of processor board System flash (Intel Strataflash)
Configuration register is 0x2102


Buford, GA
check you PM's

Johnny SSH


According to your syntax I tried:

ip domain name <hostname>
ip ddns update method <ddns_name>
  add http://<uname>:<passwd>@members.dyndns.org/nic/updatehostname=<hostname>&myip=<a>
 interval maximum 0 0 2 0
 interval minimum 0 0 2 0

With the Dialer interface being provisioned as such:

interface Dialer1
 bandwidth 448
 ip ddns update hostname <hostname>
 ip ddns update <ddns_name>
 ip address negotiated
 ip access-group 102 in
 ip inspect INBOUND in
 ip inspect OUTBOUND out
 ip nat outside
 ip virtual-reassembly
 encapsulation ppp
 dialer pool 1
 dialer-group 1
 ppp authentication chap callin
 ppp chap hostname <chap_hostname>
 ppp chap password 7 <scrt_passwd>
 ppp pap sent-username <pap_uname> password 7 <pap_passwd>
 ppp ipcp dns request
 ppp ipcp wins request
 crypto map mymap

However, running:

debug ip ddns update

does not yield anything with only 2 minute intervals.....

I **will** specify 28 days later after I start seeing something in the debug console....

Am monitoring by:

lin vty 0 4
sh log

Something is off definitely!


Vancouver, BC
I had similar issues like this a while back when getting my HE dns and ipv6 updater working...

The trick seems to be to either shut/no shut the interface that the dyndns is running on. This will obviously cause you to lose internet access.

clear int
in your case...
clear int dialer 1

Try that and let me know how it goes.