Info Error Unexpected Rcode Refused Resolving
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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 error (formerr) resolving your BIND DNS server: Jul 14 00:56:13 kla-dns-01 named[8255]: lame server 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 has asked your rcode refused dns server to look up a domain name that your server didn't know about, and when it forwarded the request to it's forwarders, the remote DNS category lame-servers {null;}; server refused to respond. A packet trace on your DNS server shows exactly what's happening: root@dns1:/# tcpdump -n -s 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
Unexpected Rcode (servfail) From Master
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 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.
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Error (network Unreachable) Resolving
Business Learn more about hiring developers or posting ads with us Server Fault Questions bind disable ipv6 Tags Users Badges Unanswered Ask Question _ Server Fault is a question and answer site for system and network administrators. Join them; it named allow-query only takes a minute: Sign up Here's how it works: 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 http://www.ericshalov.com/2015/07/14/what-does-error-unexpected-rcode-refused-mean/ 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 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 http://serverfault.com/questions/672566/unexpected-rcode-refused-eating-up-log-files 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 anywhere limit: avg 5/min burst 5 LOG level debug prefix "iptables denied: " REJECT all -- anywhere anywhere reject-with icmp-port-unreachable Chain FORWARD (policy ACCEPT) target prot opt source destination REJECT all -- anywhere anywhere reject-with icmp-port-unreachable Chain OUTPUT (policy ACCEPT) target prot opt source destination ACCEPT all -- anywhere anywhere UPDATE: I've tried the following now in named.conf.options to block recursion. allow-transfer {"none";}; allow-recursion {"none";}; recursion no; Once I did this, I am now seeing the following in syslog: Mar 4 00:02:2
] [ subject ] [ author ] There's more: both ns1.netbcp.com and ns2.netbcp.net don't respond to queries about nbc.com and ns1.netbcp.com doesn't respond over TCP. Frank From: bind-users-bounces+frnkblk=iname.com at lists.isc.org [mailto:bind-users-bounces+frnkblk=iname.com https://lists.isc.org/pipermail/bind-users/2012-October/088831.html at lists.isc.org] On Behalf Of Kevin Darcy Sent: Friday, October 12, 2012 12:48 PM Cc: bind-users at lists.isc.org Subject: Re: error (unexpected RCODE REFUSED) resolving OK, so your nbc.com/A resolving error doesn't really have anything to do with the nameservers you included in your original post. It does appear, however, that ns2.netbcp.net (205.173.93.213) is refusing requests generally for the nbc.com domain: $ dig nbc.com +buf=4096 +norec unexpected rcode @ns2.netbcp.net ; <<>> DiG 9.4.3-P3 <<>> nbc.com +buf=4096 +norec @ns2.netbcp.net ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: REFUSED, id: 1019 ;; flags: qr; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;nbc.com. IN A ;; Query time: 30 msec ;; SERVER: 205.173.93.213#53(205.173.93.213) ;; WHEN: Fri Oct 12 13:44:56 2012 info error unexpected ;; MSG SIZE rcvd: 36 ns1.netbcp.com appears to be doing the same thing. Not known whether this is something temporary (performing maintenance?), or something permanent (provider's contract lapsed, but customer never updated delegations). In any case, you have enough working authoritative nameservers for the domain, so it'll continue to resolve for you... - Kevin On 10/12/2012 1:35 PM, James Tingler wrote: I don't think that I am. I only define internal forwarders for internal zones as needed. For my root hint, standard configuration: Named.conf zone "." { type hint; file "named.ca"; Named.ca: ; <<>> DiG 9.5.0b2 <<>> +bufsize=1200 +norec NS . @a.root-servers.net ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 34420 ;; flags: qr aa; QUERY: 1, ANSWER: 13, AUTHORITY: 0, ADDITIONAL: 20 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;. IN NS ;; ANSWER SECTION: . 518400 IN NS M.ROOT-SERVERS.NET. . 518400 IN NS A.ROOT-SERVERS.NET. . 518400 IN NS B.ROOT-SERVERS.NET. . 518400 IN NS C.ROOT-SERVERS.NET. . 518400 IN NS D.ROOT-SERVERS.NET. . 518400 IN NS E.ROOT-SERVERS.NET. . 518400 IN NS F.ROOT-SERVERS.NET. . 518400 IN NS G.ROOT-SERVERS.NET. . 518400 IN NS H.ROOT-SERVERS.NET. . 518400 IN NS I.ROOT-SERVERS.NET.