Found an interesting issue at a site where the router had lost the configuration. I went out, reconfigured the router from a backup and went to save:
ROUTER#wr
startup-config file open failed (Unknown error 0)
And in the log:
*Mar 7 00:56:53.825: %SYS-4-NV_BLOCK_INITFAIL: Unable to initialize the geometry of nvram
*Mar 7 01:00:30.941: %SYS-4-NV_BLOCK_INITFAIL: Unable to initialize the geometry of nvram
We have recently started offering ADSL2+ services. Like all tier 2 ISPs in Australia, these ADSL2+ sessions are delivered to us over L2TP tunnels to our LNS. Everything was set up fine with the sessions authenticating and terminating and with the end customers able to access the internet. However, we soon had customers with issues accessing some websites. Having seen similar things before, my first thought was MTU. After some testing and eventually sending an engineer out to a customer having issues we ended up with:
interface Virtual-Template0
We found something rather strange today on our Cisco 4948s. Something that we probably wouldn't have noticed had it not been for RANCID. Our 4948s talk back to the rest of our network via OSPF. Because we only want to talk to our network via OSPF, we have "passive-interface default" as part of our OSPF configuration and have the interfaces we want specifically enabled with "no passive-interface".
