sometimes am unable to get past my ISP DNS

Uriel

This is a clone of a post I made on SA, bear with me here.

Problem description: Been having rather severe connection issues for the past month, I am able to pull and IP address from my ISP but occasionally it will enter a state where I am unable to even ping anything past their DNS server. It seems to only really affect my computer though occasionally the other computers run into a similar issue though not as sever.


Attempted fixes: I have attempted clearing my ARP cache, as someone had mentioned that it might have become corrupt, and there are a lot of static entries in it. I have also swapped out the modem and replaced my 5 year old WRT54G with a new belkin BASIC wireless router.

Recent changes: Not as far as I remember

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Operating system: Windows 7 home premium 64 bit


System specs: I built my computer myself, Athalon 64 X2, motherboard is a BIOSTAR A760G M2+, don't know what else would be relelvent to the issue

I have Googled and read the FAQ: Yes

End

Is it actually their DNS server, or is your router functioning as a dns server and that's what is getting used?

Edit: And, when you say other computers have the same issue, they're on the same LAN, yes?

Basically, Computers ---> Router ---> Modem ---> ISP?

Uriel

End wrote: »

Is it actually their DNS server, or is your router functioning as a dns server and that's what is getting used?

Edit: And, when you say other computers have the same issue, they're on the same LAN, yes?

Basically, Computers ---> Router ---> Modem ---> ISP?

yes and yes.

And I may have fixed it, I just put the DNS servers IPs in manually on the router and my network adapter.

EDIT: Nope not working, still went down for a while a bit ago.

RBach

Try some other DNS servers such as from http://www.opendns.com/.

Echo

Try Google's DNS. 8.8.8.8 and 8.8.4.4.

Trentus

I'm having a little trouble understanding exactly what the problem is (as I'm interpreting it at the moment, it doesn't really sound like a DNS issue).

So, when you start experiencing this issue, what error does your browser give you? Does it tell you it can't find a page (which generally means it couldn't resolve the hostname to an IP address), or does it tell you the connection timed out (or was reset), or something else? Browsers don't always give fantastically helpful error messages.

What I gather from what you said is that it resolves to an IP address. Jump into a command line and do an nslookup google.com or something. If it doesn't resolve the hostname, what does it tell you? Could it not find an entry? Could it not reach the DNS server?

If it can't find the DNS server, do a traceroute (tracert on windows, tracert dns.IP.addy.here) and find out where the connection gets lost. If it makes it all the way out of your local network before timing out, then there's not really much you can do about the problem other than give your ISP the results from your traceroute and hope they fix it.

If nslookup gives you an IP and says all is jolly, try and ping an external IP address (or hostname, as it should resolve fine). What does it say if it fails? What results do you get when you do a traceroute to the host?

End

If you're really reaching your ISP's DNS servers, but nothing else, it's a very high chance its on your ISP's end, because their DNS server is still going to be located on the other side of your modem. The only part that makes it suspicious is you make a distinction between computers.

I suppose it's possible that it is still an issue on your end, and somehow DNS traffic is getting through, but other traffic isn't. Trying a public DNS server might ferret that out if that's actually your issue.

MrDelish

I have a similar problem, though the most puzzling issue I've had is sometimes when connecting to a videogame server the connection will freeze to where I can't move but I'll still see updates in the game for a few minutes (kills, round ends, etc), and even voice chat. When I disconnect/drop, I can't reconnect or ping the server for at least fifteen minutes.

Not too worried about it, though, since I'm moving out in a month and a half

Uriel

Trentus wrote: »

I'm having a little trouble understanding exactly what the problem is (as I'm interpreting it at the moment, it doesn't really sound like a DNS issue).

So, when you start experiencing this issue, what error does your browser give you? Does it tell you it can't find a page (which generally means it couldn't resolve the hostname to an IP address), or does it tell you the connection timed out (or was reset), or something else? Browsers don't always give fantastically helpful error messages.

What I gather from what you said is that it resolves to an IP address. Jump into a command line and do an nslookup google.com or something. If it doesn't resolve the hostname, what does it tell you? Could it not find an entry? Could it not reach the DNS server?

If it can't find the DNS server, do a traceroute (tracert on windows, tracert dns.IP.addy.here) and find out where the connection gets lost. If it makes it all the way out of your local network before timing out, then there's not really much you can do about the problem other than give your ISP the results from your traceroute and hope they fix it.

If nslookup gives you an IP and says all is jolly, try and ping an external IP address (or hostname, as it should resolve fine). What does it say if it fails? What results do you get when you do a traceroute to the host?

Well the error it gives me isn't really helpful at all.

It just says "cannot connect to server at <website>"

And I'll try this next time I get errors.

jothki

What happens if you just try to connect to a known IP address, instead of going through a DNS? As far as I know In most cases the DNS is always going to be the first thing you connect to, so any more general connectivity issues will show up there.

Uriel

As far as I know, I can't, I just seem to hit a brick wall after the ISP's DNS server.

tried pinging google once while it was happening...

Uriel

So It just happened again, and I ran a tracert to google and sent it to my ISP, hopefully they get back to me.

Tomanta

Since DNS is just used to lookup the domain name and you usually don't route traffic through the DNS server, something doesn't add up. Either you have a routing problem or you have a DNS lookup problem.

Next time it happens try to ping 8.8.4.4 (google's DNS mentioned above). If that goes through just change the DNS servers your router uses to the google ones mentioned above, or openDNS.

Also do an ipconfig /flushdns if you haven't done that yet.

If you can't ping 8.8.4.4 then you have a routing issue. Do a tracert to that address and see how far you get.

Uriel

I just tracert'd penny-arcade.com, while the issue was going on and after my modem, it said destination protocol unreachable?

Also what the hell, I just did that flushdns command and now it's working again, temporarily probably?

I'ma try to turn of DNS caching and see if that was the issue.

Uriel

Okay so that didn't do it either.

This is really pissing me off.

Just ran a tracert to penny-arcade.com while it was working correctly too.

It was well out of my network and then started to time out.

EDIT: Also just found out how to turn off the firewall on my new router.

Dark Shroud

Check to see if your router has any updates. Also are you running bittorrent on any of those computers? That can be hell for older/cheaper routers.

And I would suggest switching to OpenDNS anyway.

OpenDNS

208.67.222.222
208.67.220.220

Dyn DNS

216.146.35.35
216.146.36.36

theclam

It's not going to let you tracert a URL if you are having DNS problems. You can only tracert an IP address. Timing out for a tracert is normal (penny-arcade.com ends with lots of time outs for me too), since some routers are configured not to return pings. I wouldn't turn off the firewall on your router. Like others have said, change your DNS server. If you still get the problem after that, then it's almost certainly a problem on your ISP's end.

Uriel

Welp, apparently it was my old router going bad and the new one having a firewall on.

Thanks for the help people, the new one is working fine now.

Uriel

Well it would seem I am going to have to replace this old and busted WRT54G which is running on it's last... It is five years old...

Any suggestions better than my shitty little belkin?

How are the new WRT54G2's?