Hey all,
I have been using an x86 router as a DNS server for my wireless customers for quite some time and until about 5 or six months ago it was working great.
Now with about 400 customers using it the Dude says it’s timing out every 15 minutes. When I do nslookups to it every other one will time out. Some times it’s fine. I’m running 6.15 on an intel Atom with 2Gig of ram and the CPU never goes above 5%.
When I throw pings out to it it reply effortlessly..
I really need help with this or I’m gonna have to come up with a better resolution server.
Maybe do a packet capture? Using Winbox, go to Tools > Packet Sniffer. Under general set Interface=all, Memory Limit=1000, File Name=DNSTest, File Limit=1000
Then under Filter set IP Protocal to 17 (UDP) and Port to 53 (DNS), Direction=Any
Then you must hit Apply, and then Start. Do your nslookups again, when one times out, click Stop and then hit the Packets button.
You’ll be able to see if RouterOS is forwarding requests/replies to the proper places, or maybe it’s an upstream DNS service not replying.
I’ll give that a try, but would the capture not be flooded with requests for actual DNS resolutions from my subscribers??
You’d run the capture for about 1 minute while you did nslookups until 1 or more timed-out. Then you’d copy the file from Winbox > Files to your local computer, load it into wireshark and apply a filter to show only requests to and from your laptop’s IP address. I think the filter would be (ip.src==192.168.1.100)||(ip.dst==192.168.1.100)) (or whatever your laptop’s IP is).
Or post the file on here. I worked with a capture file this morning that had 50,000 packets. Wireshark is very quick at filtering through them.