Men centos6.2 64bit ishlaydigan virtual quti mijoz mashinasini o'rnataman, xost mashinasi windows7 64bit va mijoz mashinasida ikkita net kartani o'rnataman, birinchi navbatda NAT rejimi, ikkinchisi faqat xost rejimi, keyin men quyidagi muammoga duch keldim. mijoz centosni ishga tushirish:
mirror.centos.org ga ping qo'yganimda, u nomga yetganga o'xshaydi:
PING mirror.centos.org (202.76.233.2) 56(84) bytes of data.
64 bytes from 202.76.233.2: icmp_seq=1 ttl=49 time=91.2 ms
Men bir xil xost nomini telnet qilganimda, u bajarilmadi:
$ telnet mirror.centos.org 80
telnet: mirror.centos.org: Name or service not known
mirror.centos.org: Host name lookup failure
lekin men to'g'ridan-to'g'ri ipni telnet qilganimda, u muvaffaqiyatli bo'ladi:
$ telnet 202.76.233.2 80
Trying 202.76.233.2...
Connected to 202.76.233.2.
Escape character is '^]'.
Mening savolim: ping muvaffaqiyatli bo'lganda, xost nomi hal qilinganga o'xshaydi, nima uchun telnetda bir xil xost nomi bo'lsa, u yana muvaffaqiyatsizlikka uchradi? (aslida yum kabi boshqa dasturda bir xil xost nomini hal qila olmaydi)
Har qanday yordam uchun rahmat.
qo'shimcha tavsiflash:
Kechirasiz, muammoni tasvirlashda xatolik bor, manully dns router tomonidan o'chirib qo'yilgan, shuning uchun muammo yana centosda sodir bo'lganga o'xshaydi. Men "telnet www.centos.org 80" ni ishga tushirganda DNS paketini olish uchun tcpdump dan foydalanaman, jurnallar ro'yxati bu erda:
16:12:15.662796 IP 192.168.116.129.54451 > 192.168.116.2.domain: 19272+ A? www.centos.org. (32)
16:12:15.662914 IP 192.168.116.129.54451 > 192.168.116.2.domain: 33092+ AAAA? www.centos.org. (32)
16:12:15.665205 IP 192.168.116.2.domain > 192.168.116.129.54451: 19272 1/0/0 A 85.12.30.227 (48)
16:12:15.667042 IP 192.168.116.2.domain > 192.168.116.129.54451: 33092- 0/0/0 (43)
16:12:15.667121 IP 192.168.116.129.47706 > 192.168.116.2.domain: 19272+ A? www.centos.org. (32)
16:12:15.667226 IP 192.168.116.129.47706 > 192.168.116.2.domain: 33092+ AAAA? www.centos.org. (32)
16:12:15.667977 IP 192.168.116.2.domain > 192.168.116.129.47706: 19272 1/0/0 A 85.12.30.227 (48)
16:12:15.670181 IP 192.168.116.2.domain > 192.168.116.129.47706: 33092- 0/0/0 (43)
16:12:15.670291 IP 192.168.116.129.34270 > 192.168.116.2.domain: 61846+ A? www.centos.org.localdomain. (44)
16:12:15.670393 IP 192.168.116.129.34270 > 192.168.116.2.domain: 7936+ AAAA? www.centos.org.localdomain. (44)
16:12:15.671208 IP 192.168.116.2.domain > 192.168.116.129.34270: 61846 NXDomain*- 0/0/0 (44)
16:12:15.673649 IP 192.168.116.2.domain > 192.168.116.129.34270: 7936- 0/0/0 (55)
16:12:15.673726 IP 192.168.116.129.49484 > 192.168.116.2.domain: 61846+ A? www.centos.org.localdomain. (44)
16:12:15.673827 IP 192.168.116.129.49484 > 192.168.116.2.domain: 7936+ AAAA? www.centos.org.localdomain. (44)
16:12:15.674595 IP 192.168.116.2.domain > 192.168.116.129.49484: 61846 NXDomain*- 0/0/0 (44)
16:12:15.676653 IP 192.168.116.2.domain > 192.168.116.129.49484: 7936- 0/0/0 (55)
3-qatorda dns-server so'ralgan manzilni qaytardi, lekin "telnet" so'rovni davom ettirdi va keyinchalik u domenga (www.centos.org.localdomain) dum qo'ydi, bu, albatta, noto'g'ri xost nomi, shuning uchun nega bu sodir bo'ldi?
