Maintained by: NLnet Labs

[Unbound-users] Unbound DDoS / reflexion attack counter-measure ?

Tom
Sat May 31 00:46:42 CEST 2014


Hey guys,

Lately, we had a few botnets that slowed down our unbounds by querying
$RANDOM.www.$website.$tokill (see dump_requestlist below for an
example). They use all the available sockets (numfiles) and then
unbound is very slow to resolve. I was wondering how can we mitigate
these kind of attacks. I tried to play with jostle-timeout but I
couldn't really see an improvement.

My setup:

server:
	verbosity: 1
	interface-automatic: yes
	outgoing-range: 950
	outgoing-num-tcp: 50
	incoming-num-tcp: 50
	so-rcvbuf: 4m
	msg-cache-size: 50m
	jostle-timeout: 1000
	rrset-cache-size: 100m
	root-hints: "named.cache"
	hide-identity: yes
	hide-version: yes
	prefetch: yes
	prefetch-key: yes
	auto-trust-anchor-file: "root.key"
	
python:
remote-control:
	control-enable: yes

Version 1.4.16
linked libs: libevent 1.4.13-stable (it uses epoll), ldns 1.6.16,
OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008 linked modules: validator iterator
configured for i386-redhat-linux-gnu on Fri Feb  3 11:22:53 EST 2012
with options: '--build=i386-koji-linux-gnu'
'--host=i386-koji-linux-gnu' '--target=i386-redhat-linux-gnu'
'--program-prefix=' '--prefix=/usr' '--exec-prefix=/usr'
'--bindir=/usr/bin' '--sbindir=/usr/sbin' '--sysconfdir=/etc'
'--datadir=/usr/share' '--includedir=/usr/include' '--libdir=/usr/lib'
'--libexecdir=/usr/libexec' '--localstatedir=/var'
'--sharedstatedir=/usr/com' '--mandir=/usr/share/man'
'--infodir=/usr/share/info' '--with-ldns=' '--with-libevent'
'--with-pthreads' '--with-ssl' '--disable-rpath' '--enable-debug'
'--disable-static' '--with-conf-file=/etc/unbound/unbound.conf'
'--with-pidfile=/var/run/unbound/unbound.pid' '--disable-gost'
'--enable-sha2'

# unbound-control dump_requestlistthread
#    type cl name    seconds    module status
    0    A IN ns2.myhostadmin.net. - iterator wait for 118.123.249.112
    1    A IN n5w50.akamai.net. - iterator wait for 184.85.248.193
    2 AAAA IN ns6-193.akamaitech.net. - iterator wait for 2.22.230.193
    3    A IN ab.www.sidear.cn. 42.189186 iterator wants A IN
ns2.myhostadmin.net.
    4    A IN af.www.sidear.cn. 13.652754 iterator wants A IN
ns2.myhostadmin.net.
    5    A IN al.www.sidear.cn. 15.726925 iterator wants A IN
ns2.myhostadmin.net.
    6    A IN ap.www.sidear.cn. 35.822279 iterator wants A IN
ns2.myhostadmin.net.
    7    A IN cb.www.sidear.cn. 36.525941 iterator wants A IN
ns2.myhostadmin.net.
    8    A IN ch.www.sidear.cn. 28.784012 iterator wants A IN
ns2.myhostadmin.net.
    9    A IN ct.www.sidear.cn. 30.623194 iterator wants A IN
ns2.myhostadmin.net.
   10    A IN cx.www.sidear.cn. 42.648666 iterator wants A IN
ns2.myhostadmin.net.
   11    A IN gd.www.sidear.cn. 47.724493 iterator wants A IN
ns2.myhostadmin.net.
   12    A IN gh.www.sidear.cn. 39.788104 iterator wants A IN
ns2.myhostadmin.net.
   13    A IN id.www.sidear.cn. 35.823329 iterator wants A IN
ns2.myhostadmin.net.
   14    A IN iz.www.sidear.cn. 50.452290 iterator wants A IN
ns2.myhostadmin.net.
   15    A IN kd.www.sidear.cn. 42.652587 iterator wants A IN
ns2.myhostadmin.net.
   16    A IN kp.www.sidear.cn. 36.959272 iterator wants A IN
ns2.myhostadmin.net.
   17    A IN kx.www.sidear.cn. 36.594089 iterator wants A IN
ns2.myhostadmin.net.
   18    A IN kz.www.sidear.cn. 48.397588 iterator wants A IN
ns2.myhostadmin.net.
   19    A IN mb.www.sidear.cn. 24.006796 iterator wants A IN
ns2.myhostadmin.net.
   20    A IN mn.www.sidear.cn. 14.528836 iterator wants A IN
ns2.myhostadmin.net.
   21    A IN ql.www.sidear.cn. 6.824257 iterator wants A IN
ns2.myhostadmin.net.
   22    A IN qr.www.sidear.cn. 4.619793 iterator wants A IN
ns2.myhostadmin.net.
   23    A IN ur.www.sidear.cn. 31.598018 iterator wants A IN
ns2.myhostadmin.net.
   24    A IN wx.www.sidear.cn. 23.644625 iterator wants A IN
ns2.myhostadmin.net.
   25    A IN yf.www.sidear.cn. 22.313281 iterator wants A IN
ns2.myhostadmin.net.
   26    A IN yl.www.sidear.cn. 50.453409 iterator wants A IN
ns2.myhostadmin.net.
   27    A IN www.huffingtonpost.com. 0.002785 iterator wait for
204.74.109.1 28    A IN apch.www.sidear.cn. 36.480382 iterator wants A
IN ns2.myhostadmin.net.
   29    A IN atoh.www.sidear.cn. 51.597774 iterator wants A IN
ns2.myhostadmin.net.
   30    A IN azcn.www.sidear.cn. 7.601601 iterator wants A IN
ns2.myhostadmin.net.
   31    A IN ctex.www.sidear.cn. 48.464616 iterator wants A IN
ns2.myhostadmin.net.
   32    A IN grkv.www.sidear.cn. 24.789270 iterator wants A IN
ns2.myhostadmin.net.
   33    A IN ibgx.www.sidear.cn. 34.850291 iterator wants A IN
ns2.myhostadmin.net.
   34    A IN ixcn.www.sidear.cn. 7.752019 iterator wants A IN
ns2.myhostadmin.net.
   35    A IN kfwb.www.sidear.cn. 23.526017 iterator wants A IN
ns2.myhostadmin.net.
   36    A IN kvah.www.sidear.cn. 1.452977 iterator wants A IN
ns2.myhostadmin.net.
   37    A IN mbqf.www.sidear.cn. 34.851145 iterator wants A IN
ns2.myhostadmin.net.
   38    A IN mjcn.www.sidear.cn. 7.603391 iterator wants A IN
ns2.myhostadmin.net.
   39    A IN ofqr.www.sidear.cn. 39.115637 iterator wants A IN
ns2.myhostadmin.net.
   40    A IN qzen.www.sidear.cn. 40.258983 iterator wants A IN
ns2.myhostadmin.net.
   41    A IN svkd.www.sidear.cn. 4.457772 iterator wants A IN
ns2.myhostadmin.net.
   42    A IN utgn.www.sidear.cn. 4.453644 iterator wants A IN
ns2.myhostadmin.net.
   43    A IN wngt.www.sidear.cn. 7.761654 iterator wants A IN
ns2.myhostadmin.net.
   44    A IN wrur.www.sidear.cn. 36.476068 iterator wants A IN
ns2.myhostadmin.net.
   45    A IN wxwj.www.sidear.cn. 40.300454 iterator wants A IN
ns2.myhostadmin.net.
   46    A IN yjyl.www.sidear.cn. 1.453848 iterator wants A IN
ns2.myhostadmin.net.
   47    A IN arqhmt.www.sidear.cn. 17.369252 iterator wants A IN
ns2.myhostadmin.net.
   48    A IN ebmpwj.www.sidear.cn. 30.374737 iterator wants A IN
ns2.myhostadmin.net.
   49    A IN efqnwr.www.sidear.cn. 6.852859 iterator wants A IN
ns2.myhostadmin.net.
   50    A IN ejuhkl.www.sidear.cn. 38.135769 iterator wants A IN
ns2.myhostadmin.net.
   51    A IN elejgp.www.sidear.cn. 22.328630 iterator wants A IN
ns2.myhostadmin.net.
   52    A IN ensrgj.www.sidear.cn. 41.439056 iterator wants A IN
ns2.myhostadmin.net.
   53    A IN evofml.www.sidear.cn. 8.495929 iterator wants A IN
ns2.myhostadmin.net.
   54    A IN klcxup.www.sidear.cn. 47.810884 iterator wants A IN
ns2.myhostadmin.net.
   55    A IN knahsr.www.sidear.cn. 17.327300 iterator wants A IN
ns2.myhostadmin.net.
   56    A IN mfenyb.www.sidear.cn. 8.225055 iterator wants A IN
ns2.myhostadmin.net.
   57    A IN ohmjyb.www.sidear.cn. 6.496341 iterator wants A IN
ns2.myhostadmin.net.
   58    A IN ovifsx.www.sidear.cn. 2.577618 iterator wants A IN
ns2.myhostadmin.net.
   59    A IN qbsnet.www.sidear.cn. 14.002211 iterator wants A IN
ns2.myhostadmin.net.
   60    A IN qdebir.www.sidear.cn. 2.579080 iterator wants A IN
ns2.myhostadmin.net.
   61    A IN qjstov.www.sidear.cn. 6.004333 iterator wants A IN
ns2.myhostadmin.net.
   62    A IN qtczod.www.sidear.cn. 8.235214 iterator wants A IN
ns2.myhostadmin.net.
   63    A IN sfgtuj.www.sidear.cn. 8.491116 iterator wants A IN
ns2.myhostadmin.net.
   64    A IN shsnif.www.sidear.cn. 6.851626 iterator wants A IN
ns2.myhostadmin.net.
   65    A IN spizir.www.sidear.cn. 14.050631 iterator wants A IN
ns2.myhostadmin.net.
   66    A IN uhwzed.www.sidear.cn. 27.213915 iterator wants A IN
ns2.myhostadmin.net.
   67    A IN utajir.www.sidear.cn. 38.068550 iterator wants A IN
ns2.myhostadmin.net.
   68    A IN wfankt.www.sidear.cn. 30.301681 iterator wants A IN
ns2.myhostadmin.net.
   69    A IN wxsxwl.www.sidear.cn. 41.365671 iterator wants A IN
ns2.myhostadmin.net.
   70    A IN ahangded.www.sidear.cn. 29.609808 iterator wants A IN
ns2.myhostadmin.net.
   71    A IN ajilujyl.www.sidear.cn. 50.807512 iterator wants A IN
ns2.myhostadmin.net.
   72    A IN ajqzcrop.www.sidear.cn. 51.094238 iterator wants A IN
ns2.myhostadmin.net.
   73    A IN anszsfcv.www.sidear.cn. 50.455123 iterator wants A IN
ns2.myhostadmin.net.
   74    A IN aritqlyf.www.sidear.cn. 50.317049 iterator wants A IN
ns2.myhostadmin.net.
   75    A IN cfypwtmd.www.sidear.cn. 9.827067 iterator wants A IN
ns2.myhostadmin.net.
   76    A IN clatwtsb.www.sidear.cn. 42.653462 iterator wants A IN
ns2.myhostadmin.net.
   77    A IN gxovkjan.www.sidear.cn. 32.918413 iterator wants A IN
ns2.myhostadmin.net.
   78    A IN qbqpupwp.www.sidear.cn. 47.787873 iterator wants A IN
ns2.myhostadmin.net.
   79    A IN qvofqbwt.www.sidear.cn. 17.846959 iterator wants A IN
ns2.myhostadmin.net.
   80    A IN qxgxevcd.www.sidear.cn. 41.909531 iterator wants A IN
ns2.myhostadmin.net.
   81    A IN utclclep.www.sidear.cn. 51.050237 iterator wants A IN
ns2.myhostadmin.net.
   82    A IN uzetiper.www.sidear.cn. 39.971235 iterator wants A IN
ns2.myhostadmin.net.
   83    A IN wduxyzyz.www.sidear.cn. 7.460363 iterator wants A IN
ns2.myhostadmin.net.
   84    A IN wfkpqfkf.www.sidear.cn. 47.733132 iterator wants A IN
ns2.myhostadmin.net.
   85    A IN wvczepkp.www.sidear.cn. 50.092583 iterator wants A IN
ns2.myhostadmin.net.
   86    A IN ylyrghid.www.sidear.cn. 41.605773 iterator wants A IN
ns2.myhostadmin.net.
   87    A IN ytidermv.www.sidear.cn. 9.828912 iterator wants A IN
ns2.myhostadmin.net.
   88    A IN ajkrutsryb.www.sidear.cn. 53.798360 iterator wants A IN
ns2.myhostadmin.net.
   89    A IN arqjgbgjin.www.sidear.cn. 15.645930 iterator wants A IN
ns2.myhostadmin.net.
   90    A IN cpidahmvqt.www.sidear.cn. 7.909781 iterator wants A IN
ns2.myhostadmin.net.
   91    A IN ehitofszoh.www.sidear.cn. 51.570466 iterator wants A IN
ns2.myhostadmin.net.
   92    A IN epghgjobyn.www.sidear.cn. 49.514039 iterator wants A IN
ns2.myhostadmin.net.
   93    A IN gbovejqbir.www.sidear.cn. 51.530852 iterator wants A IN
ns2.myhostadmin.net.
   94    A IN gripcnujkv.www.sidear.cn. 15.703299 iterator wants A IN
ns2.myhostadmin.net.
   95    A IN ijoxyribqv.www.sidear.cn. 22.093370 iterator wants A IN
ns2.myhostadmin.net.
   96    A IN ipkjwzgbsf.www.sidear.cn. 18.951809 iterator wants A IN
ns2.myhostadmin.net.
   97    A IN ivenmtylwn.www.sidear.cn. 51.300647 iterator wants A IN
ns2.myhostadmin.net.
   98    A IN krqvojmngv.www.sidear.cn. 10.421760 iterator wants A IN
ns2.myhostadmin.net.
   99    A IN mbwrinyjsr.www.sidear.cn. 27.818190 iterator wants A IN
ns2.myhostadmin.net.
100    A IN mfaperuzwj.www.sidear.cn. 10.417978 iterator wants A IN
ns2.myhostadmin.net.
101    A IN mlgpctypiv.www.sidear.cn. 7.884987 iterator wants A IN
ns2.myhostadmin.net.
102    A IN oxubapuzuf.www.sidear.cn. 22.094394 iterator wants A IN
ns2.myhostadmin.net.
103    A IN ozwxqfylkb.www.sidear.cn. 27.816673 iterator wants A IN
ns2.myhostadmin.net.
104    A IN srufqnonof.www.sidear.cn. 53.799629 iterator wants A IN
ns2.myhostadmin.net.
105    A IN upypcxurmb.www.sidear.cn. 19.002303 iterator wants A IN
ns2.myhostadmin.net.
106    A IN ynuzgzyzix.www.sidear.cn. 39.295484 iterator wants A IN
ns2.myhostadmin.net.
107    A IN ypexwpcxyn.www.sidear.cn. 50.920139 iterator wants A IN
ns2.myhostadmin.net.
108    A IN bvegojzxyzi.www.sidear.cn. 19.975944 iterator wants A IN
ns2.myhostadmin.net.
109    A IN ehbzbczqepm.www.sidear.cn. 14.415002 iterator wants A IN
ns2.myhostadmin.net.
110    A IN givnjwjnphi.www.sidear.cn. 46.720398 iterator wants A IN
ns2.myhostadmin.net.
111    A IN gonnhwgbnzl.www.sidear.cn. 42.720044 iterator wants A IN
ns2.myhostadmin.net.
112    A IN gslqbyafiqv.www.sidear.cn. 42.716279 iterator wants A IN
ns2.myhostadmin.net.
113    A IN hfptiqnjkrn.www.sidear.cn. 49.709853 iterator wants A IN
ns2.myhostadmin.net.
114    A IN hnpmvhynqhj.www.sidear.cn. 47.204509 iterator wants A IN
ns2.myhostadmin.net.
115    A IN jmxigigifrw.www.sidear.cn. 8.069125 iterator wants A IN
ns2.myhostadmin.net.
116    A IN kaxlfwkphnh.www.sidear.cn. 38.470971 iterator wants A IN
ns2.myhostadmin.net.
117    A IN kdgyfqmfbyk.www.sidear.cn. 8.068407 iterator wants A IN
ns2.myhostadmin.net.
118    A IN lskvlbsiwnz.www.sidear.cn. 27.452383 iterator wants A IN
ns2.myhostadmin.net.
119    A IN mjrhfnruxkr.www.sidear.cn. 27.518935 iterator wants A IN
ns2.myhostadmin.net.
120    A IN nvjifxlrdia.www.sidear.cn. 49.635749 iterator wants A IN
ns2.myhostadmin.net.
121    A IN qfwiowmysds.www.sidear.cn. 14.490697 iterator wants A IN
ns2.myhostadmin.net.
122    A IN rvjgiygcvtd.www.sidear.cn. 47.937117 iterator wants A IN
ns2.myhostadmin.net.
123    A IN udghnznzesb.www.sidear.cn. 24.854974 iterator wants A IN
ns2.myhostadmin.net.
124    A IN ybxikrfllfd.www.sidear.cn. 19.975561 iterator wants A IN
ns2.myhostadmin.net.
125    A IN zdpcorkvvwu.www.sidear.cn. 48.517597 iterator wants A IN
ns2.myhostadmin.net.
126    A IN anmdovchgxah.www.sidear.cn. 17.186747 iterator wants A IN
ns2.myhostadmin.net.
127    A IN anofylgdybuf.www.sidear.cn. 25.255537 iterator wants A IN
ns2.myhostadmin.net.
128    A IN clmbmpsbular.www.sidear.cn. 52.650671 iterator wants A IN
ns2.myhostadmin.net.
129    A IN ebgpajyfazev.www.sidear.cn. 41.587735 iterator wants A IN
ns2.myhostadmin.net.
130    A IN elarevyvobwl.www.sidear.cn. 49.360026 iterator wants A IN
ns2.myhostadmin.net.
131    A IN etsfkzcfgdix.www.sidear.cn. 15.725886 iterator wants A IN
ns2.myhostadmin.net.
132    A IN ezohqjmvadub.www.sidear.cn. 34.865704 iterator wants A IN
ns2.myhostadmin.net.
133    A IN gbkfcpsjgheb.www.sidear.cn. 41.515665 iterator wants A IN
ns2.myhostadmin.net.
134    A IN gpedmhabazor.www.sidear.cn. 54.426431 iterator wants A IN
ns2.myhostadmin.net.
135    A IN grkjmdkvmvkb.www.sidear.cn. 17.520398 iterator wants A IN
ns2.myhostadmin.net.
136    A IN ihaxozupcfqf.www.sidear.cn. 17.184805 iterator wants A IN
ns2.myhostadmin.net.
137    A IN inanyxebozaz.www.sidear.cn. 51.762954 iterator wants A IN
ns2.myhostadmin.net.
138    A IN inkrsbonapcd.www.sidear.cn. 19.425085 iterator wants A IN
ns2.myhostadmin.net.
139    A IN kfkvibcpijap.www.sidear.cn. 19.474776 iterator wants A IN
ns2.myhostadmin.net.
140    A IN kpijcbejencb.www.sidear.cn. 13.030587 iterator wants A IN
ns2.myhostadmin.net.
141    A IN kvexsfivyjet.www.sidear.cn. 41.586191 iterator wants A IN
ns2.myhostadmin.net.
142    A IN mhmfwvmbqhaz.www.sidear.cn. 7.046275 iterator wants A IN
ns2.myhostadmin.net.
143    A IN mhutgbevgfsx.www.sidear.cn. 28.634404 iterator wants A IN
ns2.myhostadmin.net.
144    A IN ohgzqjyzubwv.www.sidear.cn. 28.570450 iterator wants A IN
ns2.myhostadmin.net.
145    A IN ohirihyhktaj.www.sidear.cn. 49.253445 iterator wants A IN
ns2.myhostadmin.net.
146    A IN ojwvydqjopaj.www.sidear.cn. 17.477149 iterator wants A IN
ns2.myhostadmin.net.
147    A IN otavsrihgvsh.www.sidear.cn. 7.155225 iterator wants A IN
ns2.myhostadmin.net.
148    A IN otgbmdezsbgn.www.sidear.cn. 23.643597 iterator wants A IN
ns2.myhostadmin.net.
149    A IN qdelkjstgnkt.www.sidear.cn. 22.390590 iterator wants A IN
ns2.myhostadmin.net.
150    A IN qhwpkzubelil.www.sidear.cn. 23.614125 iterator wants A IN
ns2.myhostadmin.net.
151    A IN stgvmvmxylex.www.sidear.cn. 15.724926 iterator wants A IN
ns2.myhostadmin.net.
152    A IN ubovszyvmrux.www.sidear.cn. 21.482549 iterator wants A IN
ns2.myhostadmin.net.
153    A IN wrmjcdalexcj.www.sidear.cn. 25.321208 iterator wants A IN
ns2.myhostadmin.net.
154    A IN wrqnmnqfuduv.www.sidear.cn. 52.556483 iterator wants A IN
ns2.myhostadmin.net.
155    A IN ybixkdqxklqv.www.sidear.cn. 28.653361 iterator wants A IN
ns2.myhostadmin.net.
156    A IN almhihcrwbafwv.www.sidear.cn. 24.786379 iterator wants A IN
ns2.myhostadmin.net.
157    A IN averargrgbuvkl.www.sidear.cn. 50.474760 iterator wants A IN
ns2.myhostadmin.net.
158    A IN gbsngvgrmvejwb.www.sidear.cn. 24.764540 iterator wants A IN
ns2.myhostadmin.net.
159    A IN glctkrgdojwpsb.www.sidear.cn. 53.031199 iterator wants A IN
ns2.myhostadmin.net.
160    A IN ivglifkperwpgv.www.sidear.cn. 29.038691 iterator wants A IN
ns2.myhostadmin.net.
161    A IN kfevwzclwdmdoh.www.sidear.cn. 24.575344 iterator wants A IN
ns2.myhostadmin.net.
162    A IN krudkncrshifyf.www.sidear.cn. 10.024796 iterator wants A IN
ns2.myhostadmin.net.
163    A IN qtcfonetwfmfif.www.sidear.cn. 41.786544 iterator wants A IN
ns2.myhostadmin.net.
164    A IN sbojifsxmvqnkv.www.sidear.cn. 42.592631 iterator wants A IN
ns2.myhostadmin.net.
165    A IN snencdanutynkd.www.sidear.cn. 53.121954 iterator wants A IN
ns2.myhostadmin.net.
166    A IN ujyrqlahmzwngr.www.sidear.cn. 29.111417 iterator wants A IN
ns2.myhostadmin.net.
167    A IN uvonilcvcjqhax.www.sidear.cn. 24.572564 iterator wants A IN
ns2.myhostadmin.net.
168    A IN wpktklalgxqfid.www.sidear.cn. 22.094554 iterator wants A IN
ns2.myhostadmin.net.
169    A IN wrolwvihwpcfqv.www.sidear.cn. 20.213483 iterator wants A IN
ns2.myhostadmin.net.
170    A IN ybkhyncjkjmdml.www.sidear.cn. 20.214726 iterator wants A IN
ns2.myhostadmin.net.
171    A IN fbcdn-profile-a.akamaihd.net. - iterator wait for
2.22.230.129 172    A IN abupkvgrubmrwniv.www.sidear.cn. 30.228467
iterator wants A IN ns2.myhostadmin.net.
173    A IN ebgxexmtytmnczol.www.sidear.cn. 30.150206 iterator wants A
IN ns2.myhostadmin.net.
174    A IN enqlufapqlitqdif.www.sidear.cn. 6.351402 iterator wants A
IN ns2.myhostadmin.net.
175    A IN ghwdqjexkrkpwlwf.www.sidear.cn. 26.862038 iterator wants A
IN ns2.myhostadmin.net.
176    A IN gnchgvqxkrsvkfwn.www.sidear.cn. 3.332469 iterator wants A
IN ns2.myhostadmin.net.
177    A IN ifebafwtyfopyhkb.www.sidear.cn. 53.976731 iterator wants A
IN ns2.myhostadmin.net.
178    A IN ilqvcbklgrqvixin.www.sidear.cn. 3.034479 iterator wants A
IN ns2.myhostadmin.net.
179    A IN itqzydqpanubkncj.www.sidear.cn. 19.094262 iterator wants A
IN ns2.myhostadmin.net.
180    A IN ivwvqpczcfijeton.www.sidear.cn. 47.536110 iterator wants A
IN ns2.myhostadmin.net.
181    A IN oharytojsnatcnqr.www.sidear.cn. 12.400879 iterator wants A
IN ns2.myhostadmin.net.
182    A IN qxenmhizsrqvuhsp.www.sidear.cn. 6.642887 iterator wants A
IN ns2.myhostadmin.net.
183    A IN shqlgzyjinmnobon.www.sidear.cn. 26.924261 iterator wants A
IN ns2.myhostadmin.net.
184    A IN ufkhupcpgjqlqreh.www.sidear.cn. 47.538700 iterator wants A
IN ns2.myhostadmin.net.
185    A IN yfkzmnshejazefwh.www.sidear.cn. 25.165260 iterator wants A
IN ns2.myhostadmin.net.
186    A IN ynkpmvmnodclklob.www.sidear.cn. 7.818328 iterator wants A
IN ns2.myhostadmin.net.
187    A IN fbcdn-sphotos-g-a.akamaihd.net. - iterator wait for
61.213.146.4

Any ideas or suggestions are welcome.
Cheers,
Thomas