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Posted to server-user@james.apache.org by JWM <te...@malcolms.com> on 2006/05/04 16:44:51 UTC
James started not being able to find any external host
This is a very scary situation. Apparently sometime yesterday AM, James
just decided that it could no longer find any external hosts. I get a ton
of entries in the logs that say "can't find DNS entries for yahoo.com",
sbcglobal.net, verizon.net, and a ton of other completely legit domains.
I know the obvious suspect is the DNS for the server. But from that same
machine I can do nslookup and also bring up web pages for the domains James
says it can't find.
I turned on "DEBUG" level on all the logs and restarted James (not a server
reboot, just bounced James). All of a sudden, now James is happy and
finding everything.
Nothing I dislike more than problems that just 'go away' with a reboot. I
really need to figure out what could have caused this and what state James
must have gotten into. Random problems like this tend to return at the most
inconvenient times.
If you've never heard of anything like this, still please tell me what I can
do to start debugging it the next time. I'm very good at debug. I just
need to at least know the zip code of where to begin.
Thanks,
Jerry
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Epilog: James started not being able to find any external host
Posted by JWM <te...@malcolms.com>.
OK, I finally figured out what the problem was. But it was not a reboot
issue. It was indeed the addition of the "recursion no;" clause in my
named.conf file.
As it turns out, I had hardcoded the dns entries in my James conf file and
had my local host IP first. Apparently before I added the recursion clause,
my DNS server would forward the request upstream if it did not find the name
in question. When I set "recursion no;", my DNS server stopped forwarding
the request for names it didn't have configured, meaning that the only
domain names the dns server would resolve are domains I am hosting. When
James was told to use that DNS server, no external domain names were being
resolved.
So the fix was to remove my local DNS IP address from the James DNS server
list.
Thanks again, Stefano, for all of your assistance. Not a way in the world I
would have figured this out without your pointers.
Jerry
-----Original Message-----
From: Stefano Bagnara [mailto:apache@bago.org]
Sent: Thursday, May 04, 2006 12:57 PM
To: James Users List
Subject: Re: James started not being able to find any external host
I don't know what "recursion no" does.
I just know that james discover DNS servers at startup so you have to
restart james if you change the dns servers.
If you simply change the dns behaviours (and not their IPs) James uses
the correct time-to-live for the expiration of the dns records.
Stefano
JWM wrote:
> OK, We're getting to the bottom of this.... I am running a DNS server on
my
> box for my hosted domains. James has my local DNS first in the chain,
> followed by my two upstream DNSs, which points me to the following clue:
>
> I ran DNSReport.com a couple of days ago on one of my domains and got an
> error saying I needed to add "recursion no" to my DNS server config to
> prevent some sort of spoofing (DNS theory is not my forte...). I added
that
> and bounced the DNS server a day or so ago. This morning in desperation
to
> recover from the email catastrophe, I removed that line.
>
> Now, not having a clue what that recursion thing really does, my question
is
> this: Was it the fact the recursion option line was added to my DNS config
> that caused my problem? Or was it simply that for some reason I was
> required to restart James after bouncing the DNS server that caused the
> problem. In other words, is it safe to add that "recursion no" and just
> bounce James when I bounce the DNS server? Or is that line in the DNS
> config going to cause problems with James, no matter what?
>
> I really appreciate your help on this.
>
> Jerry
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Re: James started not being able to find any external host
Posted by Stefano Bagnara <ap...@bago.org>.
I don't know what "recursion no" does.
I just know that james discover DNS servers at startup so you have to
restart james if you change the dns servers.
If you simply change the dns behaviours (and not their IPs) James uses
the correct time-to-live for the expiration of the dns records.
Stefano
JWM wrote:
> OK, We're getting to the bottom of this.... I am running a DNS server on my
> box for my hosted domains. James has my local DNS first in the chain,
> followed by my two upstream DNSs, which points me to the following clue:
>
> I ran DNSReport.com a couple of days ago on one of my domains and got an
> error saying I needed to add "recursion no" to my DNS server config to
> prevent some sort of spoofing (DNS theory is not my forte...). I added that
> and bounced the DNS server a day or so ago. This morning in desperation to
> recover from the email catastrophe, I removed that line.
>
> Now, not having a clue what that recursion thing really does, my question is
> this: Was it the fact the recursion option line was added to my DNS config
> that caused my problem? Or was it simply that for some reason I was
> required to restart James after bouncing the DNS server that caused the
> problem. In other words, is it safe to add that "recursion no" and just
> bounce James when I bounce the DNS server? Or is that line in the DNS
> config going to cause problems with James, no matter what?
>
> I really appreciate your help on this.
>
> Jerry
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RE: James started not being able to find any external host
Posted by JWM <te...@malcolms.com>.
OK, We're getting to the bottom of this.... I am running a DNS server on my
box for my hosted domains. James has my local DNS first in the chain,
followed by my two upstream DNSs, which points me to the following clue:
I ran DNSReport.com a couple of days ago on one of my domains and got an
error saying I needed to add "recursion no" to my DNS server config to
prevent some sort of spoofing (DNS theory is not my forte...). I added that
and bounced the DNS server a day or so ago. This morning in desperation to
recover from the email catastrophe, I removed that line.
Now, not having a clue what that recursion thing really does, my question is
this: Was it the fact the recursion option line was added to my DNS config
that caused my problem? Or was it simply that for some reason I was
required to restart James after bouncing the DNS server that caused the
problem. In other words, is it safe to add that "recursion no" and just
bounce James when I bounce the DNS server? Or is that line in the DNS
config going to cause problems with James, no matter what?
I really appreciate your help on this.
Jerry
-----Original Message-----
From: Stefano Bagnara [mailto:apache@bago.org]
Sent: Thursday, May 04, 2006 12:29 PM
To: James Users List
Subject: Re: James started not being able to find any external host
apps/james/logs/dnsserver*.log
-------
29/12/05 10:42:51 INFO dnsserver: Autodiscovery is enabled - trying to
discover your system's DNS Servers
29/12/05 10:42:51 INFO dnsserver: No DNS servers have been specified or
found by autodiscovery - adding 127.0.0.1
29/12/05 10:42:51 DEBUG dnsserver: DNSServer init...
29/12/05 10:42:51 INFO dnsserver: DNS Server is: 127.0.0.1
29/12/05 10:42:51 DEBUG dnsserver: DNSServer ...init end
----------
Stefano
JWM wrote:
> OK, I'm with you now. You are saying that the configured DNSs for the
> server may have changed. I am running fixed IP and fixed DNS. I haven't
> reconfig'd my DNSs in months.
>
> But I'd like to pursue this further just to be sure. You referenced that
> you write the autodiscovered dns IPs in a log file. I can't seem to find
> it. What specific log file would I find that in?
>
> Thanks again.
>
> Jerry
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Re: James started not being able to find any external host
Posted by Stefano Bagnara <ap...@bago.org>.
apps/james/logs/dnsserver*.log
-------
29/12/05 10:42:51 INFO dnsserver: Autodiscovery is enabled - trying to
discover your system's DNS Servers
29/12/05 10:42:51 INFO dnsserver: No DNS servers have been specified or
found by autodiscovery - adding 127.0.0.1
29/12/05 10:42:51 DEBUG dnsserver: DNSServer init...
29/12/05 10:42:51 INFO dnsserver: DNS Server is: 127.0.0.1
29/12/05 10:42:51 DEBUG dnsserver: DNSServer ...init end
----------
Stefano
JWM wrote:
> OK, I'm with you now. You are saying that the configured DNSs for the
> server may have changed. I am running fixed IP and fixed DNS. I haven't
> reconfig'd my DNSs in months.
>
> But I'd like to pursue this further just to be sure. You referenced that
> you write the autodiscovered dns IPs in a log file. I can't seem to find
> it. What specific log file would I find that in?
>
> Thanks again.
>
> Jerry
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RE: James started not being able to find any external host
Posted by JWM <te...@malcolms.com>.
OK, I'm with you now. You are saying that the configured DNSs for the
server may have changed. I am running fixed IP and fixed DNS. I haven't
reconfig'd my DNSs in months.
But I'd like to pursue this further just to be sure. You referenced that
you write the autodiscovered dns IPs in a log file. I can't seem to find
it. What specific log file would I find that in?
Thanks again.
Jerry
-----Original Message-----
From: Stefano Bagnara [mailto:apache@bago.org]
Sent: Thursday, May 04, 2006 11:45 AM
To: James Users List
Subject: Re: James started not being able to find any external host
Sorry the correct name is "resolv.conf" and it is a linux/unix file.
If you use windows then in 2000/XP you can update the dns on-the-fly by
the control panel or it can be updated automatically using dhcp if you
have dhcp enabled and a dhcp server in the lan.
To look at your currently configured dns run "ipconfig /all" in a cmd
prompt.
If you look in the dnsserver logs that james writes in the
apps/james/logs/ folder if should write the autodiscovered dns ips at
startup. You could also check startup values from older startups if you
have older logs.
Stefano
JWM wrote:
> Stefano, Thanks so much for the quick response.
>
> Pardon my ignorance. I can't find a resolve.conf. Is that a Linux-only?
> If so, what is the Windows equivalent?
>
> Who/what would update that file?
>
> Thanks again.
>
> Jerry
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Re: James started not being able to find any external host
Posted by Stefano Bagnara <ap...@bago.org>.
Sorry the correct name is "resolv.conf" and it is a linux/unix file.
If you use windows then in 2000/XP you can update the dns on-the-fly by
the control panel or it can be updated automatically using dhcp if you
have dhcp enabled and a dhcp server in the lan.
To look at your currently configured dns run "ipconfig /all" in a cmd
prompt.
If you look in the dnsserver logs that james writes in the
apps/james/logs/ folder if should write the autodiscovered dns ips at
startup. You could also check startup values from older startups if you
have older logs.
Stefano
JWM wrote:
> Stefano, Thanks so much for the quick response.
>
> Pardon my ignorance. I can't find a resolve.conf. Is that a Linux-only?
> If so, what is the Windows equivalent?
>
> Who/what would update that file?
>
> Thanks again.
>
> Jerry
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RE: James started not being able to find any external host
Posted by JWM <te...@malcolms.com>.
Stefano, Thanks so much for the quick response.
Pardon my ignorance. I can't find a resolve.conf. Is that a Linux-only?
If so, what is the Windows equivalent?
Who/what would update that file?
Thanks again.
Jerry
-----Original Message-----
From: Stefano Bagnara [mailto:apache@bago.org]
Sent: Thursday, May 04, 2006 11:04 AM
To: James Users List
Subject: Re: James started not being able to find any external host
Mayeb your resolve.conf has been updated after james was started.
IIRC dnsjava reads the resolve.conf at startup.
Stefano
JWM wrote:
> This is a very scary situation. Apparently sometime yesterday AM, James
> just decided that it could no longer find any external hosts. I get a ton
> of entries in the logs that say "can't find DNS entries for yahoo.com",
> sbcglobal.net, verizon.net, and a ton of other completely legit domains.
>
> I know the obvious suspect is the DNS for the server. But from that same
> machine I can do nslookup and also bring up web pages for the domains
James
> says it can't find.
>
> I turned on "DEBUG" level on all the logs and restarted James (not a
server
> reboot, just bounced James). All of a sudden, now James is happy and
> finding everything.
>
> Nothing I dislike more than problems that just 'go away' with a reboot. I
> really need to figure out what could have caused this and what state James
> must have gotten into. Random problems like this tend to return at the
most
> inconvenient times.
>
> If you've never heard of anything like this, still please tell me what I
can
> do to start debugging it the next time. I'm very good at debug. I just
> need to at least know the zip code of where to begin.
>
> Thanks,
>
> Jerry
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---------------------------------------------------------------------
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Re: James started not being able to find any external host
Posted by Stefano Bagnara <ap...@bago.org>.
Mayeb your resolve.conf has been updated after james was started.
IIRC dnsjava reads the resolve.conf at startup.
Stefano
JWM wrote:
> This is a very scary situation. Apparently sometime yesterday AM, James
> just decided that it could no longer find any external hosts. I get a ton
> of entries in the logs that say "can't find DNS entries for yahoo.com",
> sbcglobal.net, verizon.net, and a ton of other completely legit domains.
>
> I know the obvious suspect is the DNS for the server. But from that same
> machine I can do nslookup and also bring up web pages for the domains James
> says it can't find.
>
> I turned on "DEBUG" level on all the logs and restarted James (not a server
> reboot, just bounced James). All of a sudden, now James is happy and
> finding everything.
>
> Nothing I dislike more than problems that just 'go away' with a reboot. I
> really need to figure out what could have caused this and what state James
> must have gotten into. Random problems like this tend to return at the most
> inconvenient times.
>
> If you've never heard of anything like this, still please tell me what I can
> do to start debugging it the next time. I'm very good at debug. I just
> need to at least know the zip code of where to begin.
>
> Thanks,
>
> Jerry
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