On Mon, August 23, 2010 15:43, Gabriel Tabares wrote:
On 23/08/2010 13:28, Joseph L. Casale wrote:
Both files are the default ones from CentOS:
So what do the host names look like that the application attempts to resolve, fully qualified or not? What does your cli based query look like?
My resolv.conf is:
search mydomain.com nameserver 10.3.2.2
The hostname of the machines is set to a FQDN server.mydomain.com.
The time it takes for the queries does not change whether we use the FQDN or just the hostname.
See below for an example (I stopped the mail server so the connection was refused).
The problems can sometimes be caused by not having reverse-DNS records for your hosts. Can you resolve to names (any name) from an IP address? e.g. nslookup 10.2.9.2?
It doesn't matter if it doesn't resolve to the rigt name, just that it resolves to something (and avoids the timeout)...
#time telnet md-mail02.mydomain.com 25 (long wait) Trying 10.2.9.2... telnet: connect to address 10.2.9.2: Connection refused telnet: Unable to connect to remote host: Connection refused
real 0m20.005s user 0m0.000s sys 0m0.005s
#time telnet md-mail02 25 (long wait) Trying 10.2.9.2... telnet: connect to address 10.2.9.2: Connection refused telnet: Unable to connect to remote host: Connection refused
real 0m10.004s user 0m0.001s sys 0m0.002s
#time telnet 10.2.9.2 25 (no wait) Trying 10.2.9.2... telnet: connect to address 10.2.9.2: Connection refused telnet: Unable to connect to remote host: Connection refused
real 0m0.005s user 0m0.001s sys 0m0.002s
Nslookup responds immediately:
#time nslookup my-mail02.mydomain.com Server: 10.2.2.254 Address: 10.2.2.254#53
Non-authoritative answer: Name: my-mail02.mydomain.com Address: 10.2.9.2
real 0m0.006s user 0m0.003s sys 0m0.003s
#time nslookup my-mail02 Server: 10.2.2.254 Address: 10.2.2.254#53
Non-authoritative answer: Name: my-mail02.mydomain.com Address: 10.2.9.2