Strange DNS problem

[mrgreen]

I've had an odd problem with DNS in BrazilFW for some time and it just bit me again, so I thought I'd ask if anyone knows why this happens or how to solve it. Sometimes, for no apparent reason, or other times after my DSL connection goes down and back up, I can't get a response from the DNS service. If I run /usr/sbin/ip.test, it reports that I am connected, that the gateway is OK, and that local IP follows standards, but it says the DNS is not working. /usr/sbin/dns.test will report no response from a.root-servers.net. I figure that restarting the DHCP/DNS daemon should fix things, but it never does. No matter how many times I execute /etc/rc.d/rc.dnsmasq, either directly, or from the web interface, DNS still won't respond. The only thing that will get DNS working again is to restart BrazilFW, then everything is fine again.

I've had this problem with the past few versions of BFW, although it may have existed before then too. I am currently running 2.31.10. Has anybody else seen this, and more to the point, has anybody figured out a way to get DNS working again without a hard reboot of BFW?

[bobbb]

I've seem this on a few occasions and usually re-boot.
First let me say that "no response from a.root-servers.net" is just a ping unless it has changed.

I bring my line down and up several times a day so I see this once in a blue moon.

My gut feeling is that it is a networking problem and not relate to DNS itself. Thought it was only me but will try to diagnose the next time.

I use to get warnings a year or so ago about being logged on (my ISP) more than once but was not. I figured that a hangup and connect in quick succession was the cause and their processing (at the ISP) had not somehow seen the first hangup or did it wrong. Normally you get the same IP again for a quick disconnect/connect.

[mrgreen]

I'd really rather not have to restart BFW when this happens if I don't have to. I'm currently letting P2P programs on several computers open their own ports with uPnP. Whenever I have to restart BFW it forces me to restart the P2P apps too since they only open the ports they want at startup. As you probably know, restarting most P2P programs moves you back to the end of the request queues. If I can't solve this any other way than by a BFW reboot, then I'd like to write a little CRON script to test the root DNS server and reboot the router if restarting dnsmasq doesn't work. This will cause me new problems however since I often am away from home for several weeks at a time and if BFW reboots there is no way to tell my P2P apps on those various PCs that they need to restart too. Grrrr.

I think I'd still be able to get in via Remote Desktop when this happens and manually restart the P2P apps, but I may not know about the reboot until long after it happens. Just finding a way to get DNS restarted properly would make everything a lot easier.

[bobbb]

I'll be a bit more attentive on this the next time and try to resolve it. Like I said, I thought it was just me. Guess not.