Jag's DNS servers - DNS not resolving

[thisisit3]

I recently started having problems with some emails not coming through to me, I traced the problem to Exim, which seems to reject the emails with "host lookup did not complete", which resulted in the reject reason "Could not complete sender verify".

So that got me thinking that the email address must have a fake hostname, but that wasn't true, emails failed in valid domains that I could easily trace from my computer.

For example, "host gmail.com" worked fine on my computer, but when running the same on the server, it resulted in a "Host gmail.com not found: 2(SERVFAIL)" error.

A few minutes later, I had identified the problem to be the Jag DNS servers that I'm using:
69.73.181.168
69.73.181.166

So I temporarily added the OpenDNS address on top of them in my /etc/resolv.conf and emails started coming through.

Has anyone seen similar problems with the Jag DNS servers?


PS:
I also tried a domain that it is hosted localy and Jag's DNS servers couldn't resolve that either, but could resolve other domains like google/yahoo/etc.

[Ron]

I have had frequent problems with dns resolution, in the past. I haven't had an issue lately.

If I recall correctly, an issue I had was the local instance of named needed to be restarted as it would slow down. A simple
wget google.com
Which should resolve a redirect then success would take 30 seconds to resolve.
I have programs that rely on dns lookups, so this failure was obvious and troublesome for me.

Btw you might consider google's opendns, with the addresses of
8.8.8.8
And
8.8.4.4

No redirects or "dns assistance" or anything sinister. Yet.

[Ron]

Interestingly, when the problem was occurring, logging into SSH would take 20ish seconds. Obviously it is performing a dns lookup of some sort.

[thisisit3]

well, I know for sure that the problem is with Jag's DNS servers because I'm using them directly (by-passing the local DNS).

try this:

nslookup <domain> <DNS server>

so

nslookup gmail.com 69.73.181.168

will use the specified (69.73.181.168) dns and will ignore the /etc/resolve.conf parameters.

this way I was able to confirm that Jag's DNS servers failed to resolve, while others worked fine (local by my ISP and the OpenDNS ones).

[JPC-Masood]

Since when did you notice this problem? We are hearing about it the first time here on the forums. Did you open a ticket with support so they can investigate?

[thisisit3]

I noticed the problem today when emails stopped coming and some clients called me to tell me emails were bouncing back. I then traced the problem as I described above.

To tell you the truth, I didn't open a ticket because when my reports are not very clear (like this time), all I get is a reply to provide my root password and not much else.

Anyway, it seems it was a temporary problem because things are working fine now.

[Ron]

Good to know. Thinking about it now, when I tried to use nslookup it wouldn't work... Probably because I was not using the IP addy directly but using the server name. DUH!

Good lord.

Glad everything is working again for you, I hope all is well in your town.

[matzah]

...
To tell you the truth, I didn't open a ticket because when my reports are not very clear (like this time), all I get is a reply to provide my root password and not much else.
...

Well, at least support is consistent with their "typical" responses... i get the same thing all the time