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Description of problem: ssh(1) seems to try only the first nameserver in /etc/resolv.conf: localhost:~> rpm -V openssh-clients localhost:~> host target.example.com target.example.com has address 192.168.1.1 localhost:~> ssh -vvv target.example.com OpenSSH_5.3p1, OpenSSL 1.0.0-fips 29 Mar 2010 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug2: ssh_connect: needpriv 0 ssh: Could not resolve hostname target.example.com: Name or service not known localhost:~> cat /etc/resolv.conf nameserver 192.168.168.254 nameserver 192.168.1.254 localhost:~> sudo vi /etc/resolv.conf localhost:~> cat /etc/resolv.conf nameserver 192.168.1.254 nameserver 192.168.168.254 localhost:~> host target.example.com target.example.com has address 192.168.1.1 localhost:~> ssh -vvv target.example.com OpenSSH_5.3p1, OpenSSL 1.0.0-fips 29 Mar 2010 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug2: ssh_connect: needpriv 0 debug1: Connecting to target.example.com [192.168.1.1] port 22. ... Version-Release number of selected component (if applicable): openssh-clients-5.3p1-52.el6_1.2.x86_64
This bug may be caused by the compatible implementation of getrrsetbyname. I will investigate it.
cannot reproduce with "dead" 1.st nameserver. There may be problem when 1.st nameserver responds that host do not exist. But this is resolver issue. Can you verify (by tcpdump, wireshark or some similar tool) the DNS responses please.
Yes, in my testing the first nameserver was not dead but the target system was unknown to it (the second nameserver had been set up for a test network while the first one was an organization wide nameserver).
redirecting to glibc
This is the correct behaviour.
Right, but since ssh and host commands behaved differently I was assuming an issue.