I have noticed a strange (for me) behavior of dns resolver in Fedora 17. If the domain name being resolved simply doesn't exists I'm provided with my IP address instead of an error. It behaves like when the search option is present in /etc/resolv.conf but it isn't. I suspect that it was added by some other script but I can't find where and how to disable it. I suspected my dns forwarder for a while but on Debian box in the same network everything works as expected - I get an error when domain name does not exist.
I have Network Manager disabled and have static IP configuration done by network service. Is there any way to change this dns resolution settings?
Mateusz Marzantowicz
On 06/15/2012 05:45 AM, Mateusz Marzantowicz wrote:
I have noticed a strange (for me) behavior of dns resolver in Fedora 17. If the domain name being resolved simply doesn't exists I'm provided with my IP address instead of an error. It behaves like when the search option is present in /etc/resolv.conf but it isn't. I suspect that it was added by some other script but I can't find where and how to disable it. I suspected my dns forwarder for a while but on Debian box in the same network everything works as expected - I get an error when domain name does not exist.
I have Network Manager disabled and have static IP configuration done by network service. Is there any way to change this dns resolution settings?
You need to provide a bit more information.....
What is the contents of your /etc/resolv.conf?
What is the output of "dig furdishcamp.com" and "host furdishcamp.com"
On 15.06.2012 00:37, Ed Greshko wrote:
On 06/15/2012 05:45 AM, Mateusz Marzantowicz wrote:
I have noticed a strange (for me) behavior of dns resolver in Fedora 17. If the domain name being resolved simply doesn't exists I'm provided with my IP address instead of an error. It behaves like when the search option is present in /etc/resolv.conf but it isn't. I suspect that it was added by some other script but I can't find where and how to disable it. I suspected my dns forwarder for a while but on Debian box in the same network everything works as expected - I get an error when domain name does not exist.
I have Network Manager disabled and have static IP configuration done by network service. Is there any way to change this dns resolution settings?
You need to provide a bit more information.....
What is the contents of your /etc/resolv.conf?
What is the output of "dig furdishcamp.com" and "host furdishcamp.com"
Ok, here you are:
1) $ cat /etc/resolv.conf nameserver 192.168.1.1
2) $ dig furdishcamp.com
; <<>> DiG 9.9.1-P1-RedHat-9.9.1-2.P1.fc17 <<>> furdishcamp.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 62207 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION: ;furdishcamp.com. IN A
;; AUTHORITY SECTION: com. 900 IN SOA a.gtld-servers.net. nstld.verisign-grs.com. 1339713695 1800 900 604800 86400
;; Query time: 41 msec ;; SERVER: 192.168.1.1#53(192.168.1.1) ;; WHEN: Fri Jun 15 00:41:55 2012 ;; MSG SIZE rcvd: 106
3) $ host furdishcamp.com Host furdishcamp.com not found: 3(NXDOMAIN)
When I do ping I get: $ ping furdishcamp.com PING furdishcamp.my.domain.here (x.y.z.9) 56(84) bytes of data.
This happens with Firefox too which is the most annoying for me because I drop to my personal web server every time the domain is not found. I'd prefer to see an error instead.
It looks like search option in resolver is enabled somewhere or for some apps.
192.168.1.1 is my router with NAT and DNS. I only found this dns issue only on Fedora boxes so far.
Mateusz Marzantowicz
On 06/15/2012 06:56 AM, Mateusz Marzantowicz wrote:
$ ping furdishcamp.com PING furdishcamp.my.domain.here (x.y.z.9) 56(84) bytes of data.
This happens with Firefox too which is the most annoying for me because I drop to my personal web server every time the domain is not found. I'd prefer to see an error instead.
It looks like search option in resolver is enabled somewhere or for some apps.
192.168.1.1 is my router with NAT and DNS. I only found this dns issue only on Fedora boxes so far.
If you change your resolv.conf to
nameserver 8.8.8.8
Does the problem change?
On 15.06.2012 01:19, Ed Greshko wrote:
On 06/15/2012 06:56 AM, Mateusz Marzantowicz wrote:
$ ping furdishcamp.com PING furdishcamp.my.domain.here (x.y.z.9) 56(84) bytes of data.
This happens with Firefox too which is the most annoying for me because I drop to my personal web server every time the domain is not found. I'd prefer to see an error instead.
It looks like search option in resolver is enabled somewhere or for some apps.
192.168.1.1 is my router with NAT and DNS. I only found this dns issue only on Fedora boxes so far.
If you change your resolv.conf to
nameserver 8.8.8.8
Does the problem change?
Nothings changed. I'm pretty much sure right now that some app or script is silently messing with resolvers configuration. It's exactly the behavior of /etc/resolve.conf with search opt configured but I have only single line there!
Mateusz Marzantowicz
On 06/15/2012 08:05 AM, Mateusz Marzantowicz wrote:
Nothings changed. I'm pretty much sure right now that some app or script is silently messing with resolvers configuration. It's exactly the behavior of /etc/resolve.conf with search opt configured but I have only single line there!
Well, it certainly is a "local" issue since none of my system exhibit that behavior.
If something comes to mind about how to track the problem I'll let you know....
Oh.... one last question...
If you add a trailing dot to the domain name does that make a difference?
ping furdishcamp.com.
On 15.06.2012 03:59, Ed Greshko wrote:
On 06/15/2012 08:05 AM, Mateusz Marzantowicz wrote:
Nothings changed. I'm pretty much sure right now that some app or script is silently messing with resolvers configuration. It's exactly the behavior of /etc/resolve.conf with search opt configured but I have only single line there!
Well, it certainly is a "local" issue since none of my system exhibit that behavior.
If something comes to mind about how to track the problem I'll let you know....
Oh.... one last question...
If you add a trailing dot to the domain name does that make a difference?
ping furdishcamp.com.
Thanks for your interest. I'm confused more and more now.
I've installed Wireshark to see what's going on behind the scene and here is a brief info of DNS related packets:
1) My IP -> router: standard query A <wrong domain name> 2) router -> My IP: standard query response, No such name 3) My IP -> router: standard query A <wrong domain name>.<my domain added here>
It looks like resolver is trying to give me the result very hard. Now I've no idea how to fix this because I already have /etc/resolv.conf containing the single nameserver line.
With trailing dot it stops after step 2 - the expected result.
It happens on two Fedora 17 boxes, one managed by Network Manager and second with network service.
Mateusz Marzantowicz
On 06/15/2012 03:54 PM, Mateusz Marzantowicz wrote:
Thanks for your interest. I'm confused more and more now.
I've installed Wireshark to see what's going on behind the scene and here is a brief info of DNS related packets:
- My IP -> router: standard query A <wrong domain name>
- router -> My IP: standard query response, No such name
- My IP -> router: standard query A <wrong domain name>.<my domain
added here>
It looks like resolver is trying to give me the result very hard. Now I've no idea how to fix this because I already have /etc/resolv.conf containing the single nameserver line.
With trailing dot it stops after step 2 - the expected result.
It happens on two Fedora 17 boxes, one managed by Network Manager and second with network service.
I would expect the behavior in step #3 if the search or domain parameters are set in /etc/resolv.conf.
They should both "No such name". When the trailing . is added it is simply saying that the host.domain-name is absolute and the value in search or domain should not be applied.
What is more curious to me is why when you enter "ping furdishcamp.com" you are getting the IP address of your system. I think that is what you are saying.
FWIW, there isn't much value in obscuring IP addresses or domain names.
On 15.06.2012 10:20, Ed Greshko wrote:
On 06/15/2012 03:54 PM, Mateusz Marzantowicz wrote:
Thanks for your interest. I'm confused more and more now.
I've installed Wireshark to see what's going on behind the scene and here is a brief info of DNS related packets:
- My IP -> router: standard query A <wrong domain name>
- router -> My IP: standard query response, No such name
- My IP -> router: standard query A <wrong domain name>.<my domain
added here>
It looks like resolver is trying to give me the result very hard. Now I've no idea how to fix this because I already have /etc/resolv.conf containing the single nameserver line.
With trailing dot it stops after step 2 - the expected result.
It happens on two Fedora 17 boxes, one managed by Network Manager and second with network service.
I would expect the behavior in step #3 if the search or domain parameters are set in /etc/resolv.conf.
They should both "No such name". When the trailing . is added it is simply saying that the host.domain-name is absolute and the value in search or domain should not be applied.
What is more curious to me is why when you enter "ping furdishcamp.com" you are getting the IP address of your system. I think that is what you are saying.
Yes, every nonexistent domain name is evaluated to <no such domain>.<my domain> which then resolves to my public IP (it is a wildcard dns record in action I think). That explains why domain name with trailing dot wasn't glued with my domain (two dots in FQDN are nonsense). I have no such behavior on Debian box without serach line explicitly set in /etc/resolve.conf. I also checked that on Windows boxes just to be sure it isn't DNS config related issue. I'm not suspecting wrong DNS configuration. I'm close to begin investigation of source code of libbind package because grepping over my file system didn't return anything related to configuration of resolver that might be useful.
Mateusz Marzantowicz
On 06/15/2012 04:43 PM, Mateusz Marzantowicz wrote:
Yes, every nonexistent domain name is evaluated to <no such domain>.<my domain> which then resolves to my public IP (it is a wildcard dns record in action I think). That explains why domain name with trailing dot wasn't glued with my domain (two dots in FQDN are nonsense). I have no such behavior on Debian box without serach line explicitly set in /etc/resolve.conf. I also checked that on Windows boxes just to be sure it isn't DNS config related issue. I'm not suspecting wrong DNS configuration. I'm close to begin investigation of source code of libbind package because grepping over my file system didn't return anything related to configuration of resolver that might be useful.
Well, you didn't show what returns in step #3. But if it returns the IP address of your public IP address then you've found what you've asked for if you have a wildcard A record.
IMO, wildcard DNS records are to be avoided like the plague.