Named Error Unexpected Rcode Refused
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"error (unexpected RCODE REFUSED)" mean? Posted by Eric on 14 July 2015, 1:29 am If you're seeing this in the /var/log/syslog on your BIND DNS server: Jul 14 00:56:13 kla-dns-01 named[8255]:
Error (formerr) Resolving
error (unexpected RCODE REFUSED) resolving '75.1.33.112.in-addr.arpa/PTR/IN': 211.136.17.105#53 ..it means that a client rcode refused dns has asked your server to look up a domain name that your server didn't know about, and when category lame-servers {null;}; it forwarded the request to it's forwarders, the remote DNS server refused to respond. A packet trace on your DNS server shows exactly what's happening: root@dns1:/# tcpdump -n -s
Lame Server Resolving
1514 -v 'port 53' tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 1514 bytes 00:56:09.686771 IP (tos 0x0, ttl 62, id 44942, offset 0, flags [DF], proto UDP (17), length 70) 10.5.11.101.42237 > 10.0.10.10.53: 17985+ PTR? 75.1.33.112.in-addr.arpa. (42) ^… One of your clients sends a request to your DNS server asking for the reverse-IP request (a "PTR" request) for
Unexpected Rcode (servfail) From Master
the domain-name corresponding to IP address 112.33.1.75 (expressed in reverse as "75.1.33.112.in-addr.arpa.") 00:56:09.687284 IP (tos 0x0, ttl 64, id 28584, offset 0, flags [none], proto UDP (17), length 81) 10.0.10.10.6374 > 10.0.0.2.53: 26305+% [1au] PTR? 75.1.33.112.in-addr.arpa. (53) ^… The DNS server forwards the reverse-IP request to it's "upstream" forwarder DNS server, 10.0.0.2. 00:56:12.218438 IP (tos 0x0, ttl 64, id 39251, offset 0, flags [none], proto UDP (17), length 81) 10.0.10.10.27738 > 211.136.20.201.53: 63185% [1au] PTR? 75.1.33.112.in-addr.arpa. (53) ^… After 3 seconds without a reply, the server sends the request to it's next forwarder, 211.136.20.201. 00:56:13.018706 IP (tos 0x0, ttl 64, id 34335, offset 0, flags [none], proto UDP (17), length 81) 10.0.10.10.37801 > 211.136.17.105.53: 55483% [1au] PTR? 75.1.33.112.in-addr.arpa. (53) ^… 800ms later, the server repeats the request to it's forwarder, 211.136.17.105. 00:56:13.251686 IP (tos 0x4, ttl 53, id 48502, offset 0, flags [none], proto UDP (17), length 81) 211.136.17.105.53 > 10.0.10.10.37801: 55483 Refused- 0/0/1 (53) ^ … The "upstream" forwarder DNS responds with the answer it received, REFUSED! Your DNS server then logs this rejection
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the company Business Learn more about hiring developers or posting ads with us Server Fault Questions Tags Users Badges named allow-query Unanswered Ask Question _ Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute: Sign up Here's how it works: http://www.ericshalov.com/2015/07/14/what-does-error-unexpected-rcode-refused-mean/ Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top unexpected RCODE REFUSED - eating up log files up vote 1 down vote favorite 1 I have a website which I host myself, and I use bind9 as my DNS server (host my own nameservers etc.). I am having a problem with http://serverfault.com/questions/672566/unexpected-rcode-refused-eating-up-log-files traffic bandwidth, and my syslog is full of the following type of issue: error (unexpected RCODE REFUSED) resolving 'target-express.com/AAAA/IN': 193.95.142.60#53 error (unexpected RCODE REFUSED) resolving 'target-express.com/A/IN': 2001:7c8:3:2::5#53 In today's syslog, there are 144258 instances of this, all related to target-express.com. My questions are: is there anything I can do firewall-wise or bind config to stop this? Why would my bind setup be trying to resolve target-express.com (it's not my domain, nothing to do with me). I have checked my forwarders in named.conf, and none of them match the IPs showing in the logs (they are all basically different IPs, not just 193.95.142.60). My iptables reads: Chain INPUT (policy ACCEPT) target prot opt source destination ACCEPT all -- anywhere anywhere REJECT all -- anywhere loopback/8 reject-with icmp-port-unreachable ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED ACCEPT tcp -- anywhere anywhere tcp dpt:http ACCEPT tcp -- anywhere anywhere tcp dpt:https ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:ssh ACCEPT udp -- anywhere anywhere udp dpt:domain ACCEPT tcp -- anywhere anywhere tcp dpt:domain ACCEPT icmp -- anywhere anywhere icmp echo-request LOG all -- anywhere an
Home Sophos UTM 9 Sophos XG Firewall Web Appliance General Malware [Beta] Malware Course Sophos Intercept X Sophos Wireless unexpected rcode Knowledge Base Blog Sophos UTM 9 Management, Networking, Logging… unexpected RCODE (REFUSED… UTM 9 Release Notes UTM Wiki Knowledge Base Sub-Groups Cancel This group named error unexpected requires membership for participation - click to join Thread Info State Not Answered Date scottj_01 Date 4 Jul 2012 8:17 PM Replies 11 replies Subscribers 0 subscribers Views 333 views English Suggested Have a cool product idea or improvement? We'd love to hear about it! Click here to go to the product suggestion community unexpected RCODE (REFUSED) resolving All- Iupgradedfrom8.102toUTM9.0latestsoftrelease.WhenIreviewedtheDNSlogthismorning,thelogwasveryfullwiththefollowingRcodeentries: 2012:07:04-15:02:05s_local_asl@OASISnamed:Lastmessage'unexpectedRCODE(RE'repeated1times,supressedbysyslog-ngonOASIS 2012:07:04-15:02:05OASISnamed[4115]:unexpectedRCODE(REFUSED)resolving'158.152.57.108.in-addr.arpa/PTR/IN':71.252.0.72#53 2012:07:04-15:02:05OASISnamed[4115]:unexpectedRCODE(REFUSED)resolving'158.152.57.108.in-addr.arpa/PTR/IN':68.238.96.72#53 2012:07:04-15:02:05OASISnamed[4115]:unexpectedRCODE(REFUSED)resolving'158.152.57.108.in-addr.arpa/PTR/IN':151.203.0.87#53 2012:07:04-15:02:05OASISnamed[4115]:unexpectedRCODE(REFUSED)resolving'120.53.194.173.in-addr.arpa/PTR/IN':216.239.38.10#53 2012:07:04-15:02:05OASISnamed[4115]:unexpectedRCODE(REFUSED)resolving'120.53.194.173.in-addr.arpa/PTR/IN':216.239.34.10#53 2012:07:04-15:02:05OASISnamed[4115]:unexpectedRCODE(REFUSED)resolving'120.53.194.173.in-addr.arpa/PTR/IN':216.239.32.10#53 2012:07:04-15:02:05OASISnamed[4115]:unexpectedRCODE(REFUSED)resolving'120.53.194.173.in-addr.arpa/PTR/IN':216.239.36.10#53 2012:07:04-15:02:06OASISnamed[4115]:unexpectedRCODE(REFUSED)resolving'120.53.194.173.in-addr.arpa/PTR/IN':216.239.34.10#53 2012:07:04-15:02:06OASISnamed[4115]:unexpectedRCODE(REFUSED)resolving'120.53.194.173.in-addr.arpa/PTR/IN':216.239.32.10#53 2012:07:04-15:02:06OASISnamed[4115]:unexpectedRCODE(REFUSED)resolving'120.53.194.173.in-addr.arpa/PTR/IN':216.239.36.10#53 2012:07:04-15:02:06OASISnamed[4115]:unexpectedRCOD