Linux客户端Active Directory身份验证在故障转移时停止工作

Linux客户端尝试通过定位DNS名称(corp.example.com)进行AD身份验证时遇到问题.我有2个域控制器服务器DC1(10.0.0.3/24),DC2(10.1.0.3/24)这两个域控制器用于corp.example.com.在开始之前,每个Linux客户端都有明确定义的2个AD服务器IP地址中的1个.我经历了用域名(corp.example.com)替换IP地址,如下面的配置中所示.经过测试,效果很好.但是,通过关闭其中一个Dome Controller服务器来测试故障转移会导致某些Linux客户端无法进行身份验证和超时.当我认为这是一个网络问题时,请查看我最初发布的
DC/DNS failover with global/common DNS roundrobin.

在Linux客户端上：

/etc/openldap/ldap.conf中

uri     ldap://DC1 ldap://DC2
    base    dc=corp,dc=example,dc=com

的/etc/krb5.conf

[libdefaults]
        default_realm = corp.example.com
        clockskew = 300
        dns_lookup_kdc
#       default_realm = EXAMPLE.COM

[realms]
corp.example.com= {
        kdc = corp.example.com
        default_domain = corp.example.com
        kpasswd_server = corp.example.com
        admin_server = corp.example.com
}
#       EXAMPLE.COM = {
#                kdc = kerberos.example.com
#               admin_server = kerberos.example.com
#       }

[logging]
        kdc = FILE:/var/log/krb5/krb5kdc.log
        admin_server = FILE:/var/log/krb5/kadmind.log
        default = SYSLOG:NOTICE:DAEMON
[domain_realm]
        .corp.example.com = corp.example.com
        .corp = corp.example.com
[appdefaults]
pam = {
        ticket_lifetime = 1d
        renew_lifetime = 1d
        forwardable = true
        proxiable = false
        minimum_uid = 1
        external = sshd
        use_shmem = sshd
        clockskew = 300
        retain_after_close = false
}

/etc/resolve.conf

search corp.example.com
nameserver 10.0.0.3
nameserver 10.1.0.3

这就是我在syslog-ng中看到的

Nov 30 09:04:56 linux_client nscd: nss_ldap: failed to bind to LDAP server ldap://ad3: Can't contact LDAP server
Nov 30 09:04:59 linux_client sshd[15585]: nss_ldap: failed to bind to LDAP server ldap://ad3: Can't contact LDAP server
Nov 30 08:50:19 linux_client sshd[15242]: Accepted keyboard-interactive/pam for jim from 10.0.0.231 port 61288 ssh2
Nov 30 08:52:02 linux_client sshd[15284]: nss_ldap: could not search LDAP server - Server is unavailable
Nov 30 08:53:09 linux_client sshd[15284]: pam_unix2(sshd:auth): conversation failed
Nov 30 08:53:16 linux_client sshd[15284]: error: ssh_msg_send: write
Nov 30 08:53:26 linux_client sshd[15284]: pam_krb5[15284]: authentication fails for 'jim' (jim@corp.example.com): Authentication failure (Cannot read password)
Nov 30 08:53:26 linux_client sshd[15284]: error: ssh_msg_send: write
Nov 30 08:56:02 linux_client sshd[15289]: nss_ldap: could not search LDAP server - Server is unavailable
Nov 30 08:56:27 linux_client sshd[15289]: pam_krb5[15289]: authentication succeeds for 'jim' (jim@corp.example.com)
Nov 30 08:57:12 linux_client sshd[15289]: nss_ldap: could not search LDAP server - Server is unavailable
Nov 30 08:57:18 linux_client sshd[15289]: _rebind_proc
Nov 30 08:57:31 linux_client sshd[15289]: _rebind_proc
Nov 30 08:57:34 linux_client sshd[15289]: _rebind_proc
Nov 30 08:57:34 linux_client sshd[15289]: pam_ldap: ldap_result Timed out
Nov 30 08:57:34 linux_client sshd[15289]: error: ssh_msg_send: write

我看起来好像没有尝试其他DC？

解决方法

/etc/openldap/ldap.conf不是使用DNS来故障转移域控制器,而是允许您使用空格分隔的ldap服务器列表.您仍然可以使用主机名而不是实际的IP地址.

例如：URI ldap：//dc01.corp.example.com ldap：//dc02.corp.example.com

有关更多信息,请参阅：http://linux.die.net/man/5/ldap.conf

我还注意到上面的2个IP地址位于不同的子网中.确保您的客户对两者都有通信.你已经调查了网络问题所以你可能没事,但我想提一下以防万一.