Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations strongm on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!

Cisco 3600 acting funny

Status
Not open for further replies.

rwhall51

IS-IT--Management
Oct 30, 2001
114
I am using a Cisco 3600 to connect to 5 remote locations and as to connect to my ISP. I have had trouble in the last 2 months with the router losing access to the internet, and loosing access to remote locations. I can not telnet in to the router or anything when this happens. All the indication lights seem fine. The only way to fix it so far is to power off and back on. What can I check to see what is going on in the router when this happens? I can't find a command to show me what errors may have been reported before it locked.
 
Set up a syslog box and send all your router messages to the syslog server. This will tell you what is going on with the router. You could see things like memory faults or interfaces going up and down.

You don't need to know UNIX or anything and there are several free syslog servers for Windows boxes.
 
Should I just do a search for syslog for windows?
 
I have downloaded it and installed it. What do I need to do on the router to start the logging?
 
Sorry, I have setup the router for logging to the correct IP, but I am not getting anything. Can anyone suggest an idea as to what I am doing wrong?
 
I had this problem once when I started working at an ISP. There had been two or three "Network Gurus" working there prior. They had to reboot their router and servers about every 2 days (This was acceptable to them and was adobpted as a SOP) The first time they lost network connectivity (I was there about two days) 5 people come running in the server room and rebooting servers and routers and switches.WHOOOOAA WHOOA WHOAA. After threatening to kick their butts and having them explain what was going on I figured out (in about 10 minutes) that they had vlsm'd a subnet wrong and about every two days a user would dial in and hit the broadcast address.

Make sure you have the following on your router:
on every interface
no ip directed-broadcast
no ip proxy-arp

Make sure you have your subnets broken out correctly.

The next time this happens don't just reboot the router. Go in and do a sh ip arp and check the MAC addresses. When I had my broadcast problem every IP address registered as one MAC address which I was able to trace back to a Lucent Portmaster.
 
I'm not sure if this will be helpful. I will check. When I notice the problem, you can't telnet into the router. Sometimes you can ping the ether. port but not telnet. The router has been fine for almost 2 years. This has just become a problem in the last few months. There have been no changes to the setup at all. I will check the no ip directed-broadcast and no ip proxy-arp.
 
maybe you could sanitize the configuration and paste it here. You should be using the console port when you have problems so you can view the arp tables and route tables. Just a thought but usually if you haven't changed the router then there is an external issue (Misconfiguration) causing the problem. Broadcast storms will cause intermittent problems especially if you have hubs.

 
I did start using the console port the last time it went down, and since then I have not had any trouble. I did see some errors, there are two serial interfaces that have been going up and down, but nothing else.
 
How can I take the "show tech-support" command and creat a text file using telnet? I think I am missing something.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top