Internet down every day - catalyst 2960

[fmylo]

Hi everyone,

I have problem with my setup which is ridiculously easy but still cannot fix it. So, the plan goes like this:

Isp router - - > 2960 switch (L2) - - > 9 access points

I have connected the ethernet line from isp router to fa0/1 and all the access points to fa0/2 - fa0/10. I made a separate vlan 99 for these ports (fa0/1-fa0/10) and configured them as:

switchport mode access

switchport access vlan 99

I gave the vlan 99 an ip 192.168.1.253 255.255.255.0 and my default gateway 192.168.1.1 (the isp router).

The issue: The internet connection is stable for only about 1 day and then goes down. And I have to restart the router to keep the connection alive. Next day the same and so on and so on...

I contacted with the isp and they didn't find any problem with my dsl line up to the router. So I suppose that I have messed it up with my configuration!!

Consider though, that when connection is OK I can ping from a single room both the default gateway and the other rooms (access points).

Can anyone help? Thank you in advance

[Richard Burts]

Thank you for posting the running config. It is pretty simple and straightforward. I do notice that most of the ports that you are using for connections include the line "switchport mode access" but that FA0/1 connecting to the outside does not include this. I do not know why this is, and am not sure whether it is significant or not. But I would be interested to know if you manually configure this line on FA0/1 whether anything changes.

I will just comment on another aspect of this running config. On interface vlan 1 you do not have any IP address. This is not necessarily a problem. But it does mean that you do not have any access to the switch other than via the console. So any maintenance you may need to perform or any troubleshooting you may need to do will have to be done through the console connection. Related to that is the configuration of ip default-gateway. If the switch has no IP address then it has no need of a default gateway. And on the vty you have configured transport input ssh. With no IP address the switch can not process ssh. If you intend at some point to configure an IP address then leaving these commands in the config is fine. If you intend to keep the switch without an IP address then you might as well remove those commands.

I am glad that the switch continues to run without issue. But I think it is premature to think about this being solved. We have pretty conclusive demonstration that there was a problem about DHCP. I don't think you have changed anything on the switch that would relate to DHCP. If you changed the DHCP lease time from 2 hours to 3 weeks then you need to wait at least 4 weeks to be sure that it is solved.

[fmylo]

Indeed, in my initial configuration I had fixed it for ssh. Then the problem occurred and I started changing-deleting things like the ip addresses on the vlans (vlan 1 or vlan 99) and my current configuration is like Dali's paintings... The reason I did this was exactly this, the DHCP (believe it or not this was my first thought)! I saw a log message about duplication of ip addresses (I don't want to confuse you, this just happened once) and I wondered what could do this. In any case, the ssh can wait for another time.

My thinking about the lease was that of a least acceptable solution. Instead of restarting the router every day, restarting it once in a month wouldn't hurt anyone. Unfortunately, "always on" option for DHCP is not available on this router model. 3 weeks was the maximum available. 

[fmylo]

Hi everyone! The connection is still up so probably it was the dhcp renewal affecting the whole system. I leave it for now that simple as it is and if anything changes I will be back. Thank you all for the useful suggestions!