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New Member

SR 520 Router No Longer Provides DHCP Address


I am configuring a Cisco SR 520 for a small business network.  I successfully configured it and synched to the ADSL (AT&T) line.  I had the network up and was configuring NAT.  I was able to successfully connect to the Internet, and then I restarted the router.   At this point, it did not autonegotiate a DHCP lease to the PC I was using for configuration.

I am no longer able to connect it at all.  I tried restarting the router, but this did not correct the issue.  I then restarted the router while holding down the reset button with a paper clip, but this did not seem to restore factory defaults since was still not responding to the config assistant or even ping..  I am not able to get connectivity to the router, so I have no way to configure it any longer.

Is there a way to restore factory defaults, or a way to determine how to reset the SR 520 to start the DHCP service again?




Re: SR 520 Router No Longer Provides DHCP Address

You can find the appropriate default configuration file for your SR520 model here:

Then TFTP it to your flash and copy it to startup-config, then reload.

This is a clean slate....

New Member

Re: SR 520 Router No Longer Provides DHCP Address

Thanks for the quick reply.

I assume that I will need to use the console port on the SR 520 through a serial jack on a computer.

I had been using the Configuration Assistant, not the CLI port.

Once I make sure I have the correct file in the startup-config directory, will it use this file during a normal boot?  Or do I need to hold the reset pin down during the first 5 seconds?

Re: SR 520 Router No Longer Provides DHCP Address

Oh even better.  I believe CCA allows you to restore the SR520 to factory defaults via the maintenance drawer.

There is a RESET/RESTART GUI in that drawer.

Try that firt by all means!!!  CCA 2.1 is the latest CCA:

If that didnt work, then you would telnet/SSH to the IP address of the SR520 on the data lan and TFTP the default config to the router and do what I said and then just reload the router.

But to avoid all these time consuming steps, try CCA first.....


New Member

Re: SR 520 Router No Longer Provides DHCP Address

I am impressed by how quick and accurate the web support is.  Kudos to Cisco.

I used the restart feature from the CCA 2.1 maintenance drawer initially, but the router lost communication with the PC.

I am having trouble setting up Hyper terminal.  I just read a post that I should use PuTTY instead.  I am about to download this possible that Hyper terminal won't work properly?

New Member

Re: SR 520 Router No Longer Provides DHCP Address

PuTTY worked fine and I was able to review the existing config file.  I ended up copying the factory default by entering each command by hand to get the router boot strapped.  It took a while, but worked.  Thanks.

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