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[TIGGE #JRQ-909114]: Re: Modified LDM configurations in CMA

Baudouin,

> I will check with out system guys, but "nslookup", "host" and "dig" all
> work on the same machine:
> 
> ldm@tigge-ldm:~> "nslookup"  tigge-ldm.cma.gov.cn
> Server:         193.61.196.131
> Address:        193.61.196.131#53
> 
> Non-authoritative answer:
> Name:   tigge-ldm.cma.gov.cn
> Address: 219.239.44.65
> 
> ldm@tigge-ldm:~> host tigge-ldm.cma.gov.cn
> tigge-ldm.cma.gov.cn has address 219.239.44.65
> 
> ldm@tigge-ldm:~> dig tigge-ldm.cma.gov.cn
> 
> ; <<>> DiG 9.3.1 <<>> tigge-ldm.cma.gov.cn
> ;; global options:  printcmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 52635
> ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 0
> 
> ;; QUESTION SECTION:
> ;tigge-ldm.cma.gov.cn.          IN      A
> 
> ;; ANSWER SECTION:
> tigge-ldm.cma.gov.cn.   68951   IN      A       219.239.44.65
> 
> ;; AUTHORITY SECTION:
> cma.gov.cn.             21569   IN      NS      dns.cma.gov.cn.
> cma.gov.cn.             21569   IN      NS      dns2.cma.gov.cn.
> 
> ;; Query time: 0 msec
> ;; SERVER: 193.61.196.131#53(193.61.196.131)
> ;; WHEN: Thu Jul 13 17:07:42 2006
> ;; MSG SIZE  rcvd: 91

I don't know about host(1), but nslookup(1) and dig(1) communicate
directly with a DNS server in order to convert an IP  address into
a hostname: they don't, necessarily, use the same sequence of steps
as the gethostbyaddr(1) system-call that the LDM uses.

By the way, the file that often determines the sequence of steps
used by gethostbyaddr(1) to resolve an IP address is /etc/nsswitch.conf.
The keyword "file" means to use /etc/hosts and the keyword "dns" means
to use a DNS server.

> And gethostbyaddr() works for other sites. I was just wondering if you
> have seen similar problems in the past.

We've seen a few, similar problems and the cause has always been a
misconfigured DNS system.

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: JRQ-909114
Department: Support IDD TIGGE
Priority: Normal
Status: Closed