Discussion:
Multiple SERVFAIL/REFUSED unexpected RCODE
(too old to reply)
Mik J
2016-05-03 10:55:36 UTC
Permalink
Hello,
In my named.log I can see a lot of SERVFAIL/REFUSED unexpected RCODE messages. Most of the time someone tries to resolve a PTR
I can see an average of 10 messages per second like these
May  3 10:46:26 dns named[7228]: REFUSED unexpected RCODE resolving 'x.204.99.116.in-addr.arpa/PTR/IN': 203.113.131.x#53
May  3 10:46:26 dns named[7228]: SERVFAIL unexpected RCODE resolving 'x.16.165.88.in-addr.arpa/PTR/IN': 193.0.9.x#53

The PTR records don't belong to me and the remote DNS servers are located around the world.
Does anyone has an understanding of why I receive these type of requests ? Why do they query my DNS servers ?
Thank you
Mark Andrews
2016-05-03 11:30:00 UTC
Permalink
Post by Mik J
Hello,
In my named.log I can see a lot of SERVFAIL/REFUSED unexpected RCODE
messages. Most of the time someone tries to resolve a PTR
I can see an average of 10 messages per second like these
May  3 10:46:26 dns named[7228]: REFUSED unexpected RCODE resolving
'x.204.99.116.in-addr.arpa/PTR/IN': 203.113.131.x#53
May  3 10:46:26 dns named[7228]: SERVFAIL unexpected RCODE resolving
'x.16.165.88.in-addr.arpa/PTR/IN': 193.0.9.x#53
The PTR records don't belong to me and the remote DNS servers are located
around the world.
Does anyone has an understanding of why I receive these type of requests
? Why do they query my DNS servers ?
Thank you
Something on your network is trying to convert 116.00.204.x and
88.165.16.x addresses to names, presumably because they are seeing
traffic from those addresses. In both cases there appears to be
broken delegations involved.

REFUSED usually means that the server is not configured for the
zone.

SERVFAIL usually means that the server is configured for the zone
but doesn't have a current copy.

You could use whois to try to contact the administrators of these
zones to correct the servers or remove the delegations.

Mark
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: ***@isc.org
Mik J
2016-05-03 13:25:59 UTC
Permalink
Hello Mark,
Thank you for your answer. I'm not sure I've understood everything but I'll read it numerous times if necessary.I have ACLs so I'm not surprised to see these REFUSED, I also understand the SERVFAIL meaning.
I'm just trying to figure out where the problem comes from.You seem to point out a device which should be on my network and who queries a PTR (something like a mail server which want to check the domain of the user who sent the email)

What I didn't understand is"You could use whois to try to contact the administrators of these zones to correct the servers or remove the delegations."You mean this one "x.204.99.116.in-addr.arpa" which appeared in my logs ?
Regards
Post by Mik J
Hello,
In my named.log I can see a lot of SERVFAIL/REFUSED unexpected RCODE
messages. Most of the time someone tries to resolve a PTR
I can see an average of 10 messages per second like these
May  3 10:46:26 dns named[7228]: REFUSED unexpected RCODE resolving
'x.204.99.116.in-addr.arpa/PTR/IN': 203.113.131.x#53
May  3 10:46:26 dns named[7228]: SERVFAIL unexpected RCODE resolving
'x.16.165.88.in-addr.arpa/PTR/IN': 193.0.9.x#53
The PTR records don't belong to me and the remote DNS servers are located
around the world.
Does anyone has an understanding of why I receive these type of requests
? Why do they query my DNS servers ?
Thank you
Something on your network is trying to convert 116.00.204.x and
88.165.16.x addresses to names, presumably because they are seeing
traffic from those addresses.  In both cases there appears to be
broken delegations involved.

REFUSED usually means that the server is not configured for the
zone.

SERVFAIL usually means that the server is configured for the zone
but doesn't have a current copy.

You could use whois to try to contact the administrators of these
zones to correct the servers or remove the delegations.

Mark
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                INTERNET: ***@isc.org
Barry Margolin
2016-05-03 14:08:44 UTC
Permalink
Post by Mik J
Hello Mark,
Thank you for your answer. I'm not sure I've understood everything but I'll
read it numerous times if necessary.I have ACLs so I'm not surprised to see
these REFUSED, I also understand the SERVFAIL meaning.
Your ACL is not relevant. The REFUSED response is coming from the server
the reverse zone is delegated to.
Post by Mik J
I'm just trying to figure out where the problem comes from.You seem to point
out a device which should be on my network and who queries a PTR (something
like a mail server which want to check the domain of the user who sent the
email)
The problem comes from bad reverse DNS delegations of remote addresses.
Unfortunately, this has always been very common.
Post by Mik J
What I didn't understand is"You could use whois to try to contact the
administrators of these zones to correct the servers or remove the
delegations."You mean this one "x.204.99.116.in-addr.arpa" which appeared in
my logs ?
Regards
whois -h whois.apnic.net 116.99.204.0

role: VIETEL IPADMIN GROUP
address: 1 Tran Huu Duc, My Dinh, Tu Liem, Hanoi
country: VN
phone: +84-9-83000456
fax-no: +84-4-38460486
e-mail: ***@viettel.com.vn
remarks: send spam and abuse report to ***@viettel.com.vn

whois 88.165.16.0

role: Administrative Contact for ProXad
address: Free SAS / ProXad
address: 8, rue de la Ville L'Eveque
address: 75008 Paris
phone: +33 1 73 50 20 00
fax-no: +33 1 73 92 25 69
remarks: trouble: Information: http://www.proxad.net/
remarks: trouble: Spam/Abuse requests:
mailto:***@proxad.net
admin-c: APfP1-RIPE
tech-c: TPfP1-RIPE
nic-hdl: ACP23-RIPE
mnt-by: PROXAD-MNT
abuse-mailbox: ***@proxad.net
created: 2002-06-26T12:46:56Z
last-modified: 2013-08-01T12:16:00Z
source: RIPE # Filtered
Post by Mik J
Post by Mik J
Hello,
In my named.log I can see a lot of SERVFAIL/REFUSED unexpected RCODE
messages. Most of the time someone tries to resolve a PTR
I can see an average of 10 messages per second like these
May  3 10:46:26 dns named[7228]: REFUSED unexpected RCODE resolving
'x.204.99.116.in-addr.arpa/PTR/IN': 203.113.131.x#53
May  3 10:46:26 dns named[7228]: SERVFAIL unexpected RCODE resolving
'x.16.165.88.in-addr.arpa/PTR/IN': 193.0.9.x#53
The PTR records don't belong to me and the remote DNS servers are located
around the world.
Does anyone has an understanding of why I receive these type of requests
? Why do they query my DNS servers ?
Thank you
Something on your network is trying to convert 116.00.204.x and
88.165.16.x addresses to names, presumably because they are seeing
traffic from those addresses.  In both cases there appears to be
broken delegations involved.
REFUSED usually means that the server is not configured for the
zone.
SERVFAIL usually means that the server is configured for the zone
but doesn't have a current copy.
You could use whois to try to contact the administrators of these
zones to correct the servers or remove the delegations.
Mark
--
Barry Margolin
Arlington, MA
Mik J
2016-05-05 08:38:15 UTC
Permalink
Thank you guys for your answers.
Post by Mik J
Hello Mark,
Thank you for your answer. I'm not sure I've understood everything but I'll
read it numerous times if necessary.I have ACLs so I'm not surprised to see
these REFUSED, I also understand the SERVFAIL meaning.
Your ACL is not relevant. The REFUSED response is coming from the server
the reverse zone is delegated to.
Post by Mik J
I'm just trying to figure out where the problem comes from.You seem to point
out a device which should be on my network and who queries a PTR (something
like a mail server which want to check the domain of the user who sent the
email)
The problem comes from bad reverse DNS delegations of remote addresses.
Unfortunately, this has always been very common.
Post by Mik J
What I didn't understand is"You could use whois to try to contact the
administrators of these zones to correct the servers or remove the
delegations."You mean this one "x.204.99.116.in-addr.arpa" which appeared in
my logs ?
Regards
whois -h whois.apnic.net 116.99.204.0

role:          VIETEL IPADMIN GROUP
address:        1 Tran Huu Duc, My Dinh, Tu Liem, Hanoi
country:        VN
phone:          +84-9-83000456
fax-no:        +84-4-38460486
e-mail:        ***@viettel.com.vn
remarks:        send spam and abuse report to ***@viettel.com.vn

whois 88.165.16.0

role:          Administrative Contact for ProXad
address:        Free SAS / ProXad
address:        8, rue de la Ville L'Eveque
address:        75008 Paris
phone:          +33 1 73 50 20 00
fax-no:        +33 1 73 92 25 69
remarks:        trouble:      Information: http://www.proxad.net/
remarks:        trouble:      Spam/Abuse requests:
mailto:***@proxad.net
admin-c:        APfP1-RIPE
tech-c:        TPfP1-RIPE
nic-hdl:        ACP23-RIPE
mnt-by:        PROXAD-MNT
abuse-mailbox:  ***@proxad.net
created:        2002-06-26T12:46:56Z
last-modified:  2013-08-01T12:16:00Z
source:        RIPE # Filtered
Post by Mik J
 
 
 
Mi
Post by Mik J
Hello,
In my named.log I can see a lot of SERVFAIL/REFUSED unexpected RCODE
messages. Most of the time someone tries to resolve a PTR
I can see an average of 10 messages per second like these
May  3 10:46:26 dns named[7228]: REFUSED unexpected RCODE resolving
'x.204.99.116.in-addr.arpa/PTR/IN': 203.113.131.x#53
May  3 10:46:26 dns named[7228]: SERVFAIL unexpected RCODE resolving
'x.16.165.88.in-addr.arpa/PTR/IN': 193.0.9.x#53
The PTR records don't belong to me and the remote DNS servers are located
around the world.
Does anyone has an understanding of why I receive these type of requests
? Why do they query my DNS servers ?
Thank you
Something on your network is trying to convert 116.00.204.x and
88.165.16.x addresses to names, presumably because they are seeing
traffic from those addresses.  In both cases there appears to be
broken delegations involved.
REFUSED usually means that the server is not configured for the
zone.
SERVFAIL usually means that the server is configured for the zone
but doesn't have a current copy.
You could use whois to try to contact the administrators of these
zones to correct the servers or remove the delegations.
Mark
--
Barry Margolin
Arlington, MA

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