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DNS проблем


Тодор Лазаров

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снощи имаш следния проблем

имах вдигане на пинговете към lan-a от който идва нета

прикачената картинка

и същевремено в syslog.log се натрупаха огромно количество записи от рода

Jul 2 23:04:20 mecho named[28993]: client 69.63.143.139#477: error sending response: unexpected error

Jul 2 23:04:20 mecho named[28993]: client 69.63.143.139#476: error sending response: unexpected error

Jul 2 23:04:20 mecho named[28993]: client 69.63.143.139#53: error sending response: unexpected error

Jul 2 23:04:20 mecho named[28993]: client 69.63.143.139#474: error sending response: unexpected error

Jul 2 23:04:20 mecho named[28993]: client 69.63.143.139#480: error sending response: unexpected error

Jul 2 23:04:20 mecho named[28993]: client 69.63.143.139#479: error sending response: unexpected error

Jul 2 23:04:20 mecho named[28993]: client 69.63.143.139#480: error sending response: unexpected error

Jul 2 23:04:20 mecho named[28993]: client 69.63.143.139#477: error sending response: unexpected error

Jul 2 23:04:20 mecho named[28993]: client 69.63.143.139#474: error sending response: unexpected error

Jul 2 23:04:20 mecho named[28993]: client 69.63.143.139#53: error sending response: unexpected error

Jul 2 23:04:20 mecho named[28993]: client 69.63.143.139#478: error sending response: unexpected error

Jul 2 23:04:20 mecho named[28993]: client 69.63.143.139#475: error sending response: unexpected error

Jul 2 23:04:20 mecho named[28993]: client 69.63.143.139#476: error sending response: unexpected error

Jul 2 23:04:21 mecho named[28993]: client 69.63.143.139#475: error sending response: unexpected error

на какво може да се дължи ???

post-5-0-07449200-1341297612_thumb.png

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  • Administrator

В конфа си опиши мрежите на който е разрешено да обслужва само.Провери и колко трафик/пакети влизат/излизат към/от машината. Виж си натоварването на системата и ако има товар от кой процес идва. Рестартираи си днс-а като за начало :)

Use since

OpenBSD 3.x

FreeBSD 4.x

Centos 5.x Debian 3.x Ubuntu 7.x

Аз съм фен на OpenWRT.

 

Горчивината от лошото качество остава дълго след като е преминало удоволствието от ниската цена.

_____________________________

___|____|____|____|____|____|__

_|____|____|____|____|____|____

___|____|_ Удряй _|____|____|__

_|____|___ главата ___|____|____

___|____|_ си тук!! |____|____|__

_|____|____|____|____|____|____

___|____|____|____|____|____|__

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с ограничаване на заявките

Jul 3 10:50:35 mecho named[11254]: client 95.211.90.81#21: query (cache) 'ripe.net/ANY/IN' denied

Jul 3 10:50:35 mecho named[11254]: client 95.211.90.81#23: query (cache) 'ripe.net/ANY/IN' denied

Jul 3 10:50:35 mecho named[11254]: client 95.211.90.81#24: query (cache) 'ripe.net/ANY/IN' denied

Jul 3 10:50:35 mecho named[11254]: client 95.211.90.81#53: query (cache) 'ripe.net/ANY/IN' denied

Jul 3 10:50:35 mecho named[11254]: client 95.211.90.81#18: query (cache) 'ripe.net/ANY/IN' denied

Jul 3 10:50:35 mecho named[11254]: client 95.211.90.81#23: query (cache) 'ripe.net/ANY/IN' denied

Jul 3 10:50:35 mecho named[11254]: client 95.211.90.81#22: query (cache) 'ripe.net/ANY/IN' denied

Jul 3 10:50:35 mecho named[11254]: client 95.211.90.81#20: query (cache) 'ripe.net/ANY/IN' denied

Jul 3 10:50:35 mecho named[11254]: client 95.211.90.81#24: query (cache) 'ripe.net/ANY/IN' denied

Jul 3 10:50:35 mecho named[11254]: client 95.211.90.81#21: query (cache) 'ripe.net/ANY/IN' denied

частично се намалява jitter-a

сега блокирам с iptables за dport 53 за udp

iptables -I INPUT -p udp -s 95.211.90.81 --dport 53 -j DROP

трафика иначе не е голям

Ужас нищо не помага ....

12:36:11.708570 IP (tos 0x0, ttl 115, id 15239, offset 0, flags [DF], proto UDP (17), length 66) 69.63.143.139.domain > comnet-host5.sarnica.net.domain: [no cksum] 952+ [1au] ANY? ripe.net. ar: . OPT UDPsize=4096 OK (38)

0x0000: 4500 0042 3b87 4000 7311 081e 453f 8f8b E..B;.@.s...E?..

0x0010: 5436 9b05 0035 0035 002e 0000 03b8 0100 T6...5.5........

0x0020: 0001 0000 0000 0001 0472 6970 6503 6e65 .........ripe.ne

0x0030: 7400 00ff 0001 0000 2910 0000 0080 0000 t.......).......

0x0040: 0000 ..

12:36:11.708582 IP (tos 0x0, ttl 115, id 15268, offset 0, flags [DF], proto UDP (17), length 66) 69.63.143.139.domain > comnet1-host18.sarnica.net.domain: [no cksum] 952+ [1au] ANY? ripe.net. ar: . OPT UDPsize=4096 OK (38)

0x0000: 4500 0042 3ba4 4000 7311 e9f3 453f 8f8b E..B;.@.s...E?..

0x0010: 5436 b912 0035 0035 002e 0000 03b8 0100 T6...5.5........

0x0020: 0001 0000 0000 0001 0472 6970 6503 6e65 .........ripe.ne

0x0030: 7400 00ff 0001 0000 2910 0000 0080 0000 t.......).......

0x0040: 0000

това е извадка от tcpdump-a

post-5-0-71036900-1341302102_thumb.png

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  • Administrator

Ми ти нищо не си направил, днс-а ти е отворен към света. Може би имаш прекалено много заявки,флуд на днс-порта .. .Дори и да нямаш трафик,ако ти идват мнго малки пакети (udp) пак ще ти се вдига товар.

Use since

OpenBSD 3.x

FreeBSD 4.x

Centos 5.x Debian 3.x Ubuntu 7.x

Аз съм фен на OpenWRT.

 

Горчивината от лошото качество остава дълго след като е преминало удоволствието от ниската цена.

_____________________________

___|____|____|____|____|____|__

_|____|____|____|____|____|____

___|____|_ Удряй _|____|____|__

_|____|___ главата ___|____|____

___|____|_ си тук!! |____|____|__

_|____|____|____|____|____|____

___|____|____|____|____|____|__

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