Troubeshooling ideas

[jdvilla]

I have a development server that I've been using for some years now. The other day, it just stopped responding to requests from the outside world (this machine sits on my DMZ). I was able to log into another machine on the DMZ just fine and all other machines on the DMZ are working just great. Once I logged into one of the machines on the DMZ I tried logging into the development box and it worked, very slowly, but it worked. So, once logged in, I tried pinging several domains by name and IP. Nothing worked. I tried tracerouting to my WAN router and it worked fine. But when I tried tracerouting to another another machine on the same DMZ network, it would fail.

So, after much scratching my head, I decided to take the machine from my DMZ onto my LAN and it worked just fine. So, I put the machine back onto the DMZ and changed it's DMZ IP address (they are all static of course) and it's worked fine again. Also, before when I had the issue, I would issue 'route' and it would take a while before it showed my gateway. Now, with the new IP address, everything is fine.

Any ideas? Could it be that there is a conflict on my network, which I doubt because all IP's are static and assigned only by me.

I find this very weird.

[DSwain]

With my server, I had some issues with speed for a while. I realized that one of the mistakes I made was when assigning a gateway address. I used the address of the actual internet connection as opposed to the router. Doing this opened everything up and got things working properly again. You may want to check what address you're giving the server to point towards the gateway/router.

[gtmtnbiker98]

It sounds like a DNS issue and your box is timing out on DNS requests. Were you having difficulty by pinging by IP as compared to FQDN? I don't think that it would be a gateway issue, either packets leave or they don't. If any of the packets left, then it is most likely a DNS or NIC issue.

[knute]

First two questions for troubleshooting a network:

1. Did it ever work?

Yes. You mentioned that in your post.

2. What changed?

Did a new server get installed/removed? Router changed?
Since changing the IP fixed the issue, then there could be some sort of routing issue. Maybe subdomain mistype?
If nothing changed, I'ld start looking at hardware issues.

HTH