Red Hat 8通过ODBC与FreeTDS无法连接MS SQL 2016 SP2求助

在Red Hat 8系统中尝试连接MS SQL 2016 SP2，使用FreeTDS和微软ODBC两种方式均失败。已知Windows 10可正常连接该数据库，且此Linux服务器能连接其他带自签名证书的MS SQL Server；目标服务器原本无证书，安装证书后问题仍未解决。

FreeTDS连接情况 #

执行命令：

tsql -S server_name -p 1433 -D db_name -U user_name -P pwd

错误日志：

log.c:187:Starting log file for FreeTDS 1.3.13
        on 2023-03-29 16:26:07 with debug flags 0x4fff.
dblib.c:1187:tdsdbopen(0x55590bb585b0, servername.domain.int:1433, [microsoft])
dblib.c:1213:tdsdbopen: dbproc->dbopts = 0x55590bc57890
dblib.c:1224:tdsdbopen: tds_set_server(0x55590bc256d0, "servername.domain.int:1433")
dblib.c:251:dblib_get_tds_ctx(void)
dblib.c:1241:tdsdbopen: About to call tds_read_config_info...
config.c:170:Getting connection information for [servername.domain.int:1433].
config.c:174:Attempting to read conf files.
config.c:362:... $FREETDSCONF not set.  Trying $FREETDS/etc.
config.c:375:... $FREETDS not set.  Trying $HOME.
config.c:301:Could not open '/home/orch_dev/.freetds.conf' ((.freetds.conf)).
config.c:301:Could not open '/usr/local/etc/freetds.conf' ((default)).
config.c:362:... $FREETDSCONF not set.  Trying $FREETDS/etc.
config.c:375:... $FREETDS not set.  Trying $HOME.
config.c:301:Could not open '/home/orch_dev/.freetds.conf' ((.freetds.conf)).
config.c:301:Could not open '/usr/local/etc/freetds.conf' ((default)).
config.c:833:Setting 'dump_file' to 'stdout' from $TDSDUMP.
config.c:724:tds_config_login: client_charset is UTF-8.
config.c:733:tds_config_login: database_name is CM_SIM.
config.c:833:Setting 'dump_file' to 'stdout' from $TDSDUMP.
dblib.c:1268:tdsdbopen: Calling tds_connect_and_login(0x55590bc44a40, 0x55590bc29310)
iconv.c:367:tds_iconv_open(0x55590bc342e0, UTF-8)
iconv.c:198:local name for ISO-8859-1 is ISO-8859-1
iconv.c:198:local name for UTF-8 is UTF-8
iconv.c:198:local name for UCS-2LE is UCS-2LE
iconv.c:198:local name for UCS-2BE is UCS-2BE
iconv.c:389:setting up conversions for client charset "UTF-8"
iconv.c:391:preparing iconv for "UTF-8" <-> "UCS-2LE" conversion
iconv.c:430:tds_iconv_open: done
net.c:391:Connecting with protocol version 7.4
net.c:318:Connecting to 10.22.222.222 port 1433
net.c:340:tds_setup_socket: connect(2) returned "Operation now in progress"
net.c:528:tds_open_socket() succeeded
packet.c:852:Sending packet
packet.c:361:timeout
util.c:333:tdserror(0x7fff3c1b3070, 0x55590bc44a40, 20003, 115)
util.c:363:tdserror: client library returned TDS_INT_CANCEL(2)
util.c:386:tdserror: returning TDS_INT_CANCEL(2)
query.c:3757:tds_disconnect()
util.c:179:Changed query state from IDLE to DEAD
packet.c:539:Read attempt when state is TDS_DEAD
login.c:599:login packet rejected
util.c:333:tdserror(0x7fff3c1b3070, 0x55590bc44a40, 20002, 0)
util.c:363:tdserror: client library returned TDS_INT_CANCEL(2)
util.c:386:tdserror: returning TDS_INT_CANCEL(2)
net.c:391:Connecting with protocol version 5.0
net.c:318:Connecting to 10.22.222.222 port 1433
net.c:340:tds_setup_socket: connect(2) returned "Operation now in progress"
net.c:528:tds_open_socket() succeeded
token.c:418:tds_process_login_tokens()
packet.c:361:timeout
util.c:333:tdserror(0x7fff3c1b3070, 0x55590bc44a40, 20003, 115)
util.c:363:tdserror: client library returned TDS_INT_CANCEL(2)
util.c:386:tdserror: returning TDS_INT_CANCEL(2)
query.c:3757:tds_disconnect()
mem.c:656:tds_free_all_results()
util.c:179:Changed query state from IDLE to WRITING
util.c:333:tdserror(0x7f8fe33da960, 0x55590bc44a40, 20003, 110)
util.c:369:tdserror: client library not called because either tds_ctx (0x7f8fe33da960) or tds_ctx->err_handler is NULL
util.c:386:tdserror: returning TDS_INT_CANCEL(2)
query.c:3757:tds_disconnect()

微软ODBC连接情况 #

执行命令：

isql -v -k 'DRIVER={ODBC Driver 18 for SQL Server};SERVER=server_name,1433;DATABASE=db_name ;UID=user_name;PWD=pwd'

错误日志：

[S1T00][Microsoft][ODBC Driver 18 for SQL Server]Login timeout expired
[08001][Microsoft][ODBC Driver 18 for SQL Server]TCP Provider: Timeout error [258].
[08001][Microsoft][ODBC Driver 18 for SQL Server]Unable to complete login process due to delay in prelogin response
[ISQL]ERROR: Could not SQLDriverConnect

已知信息 #

• Windows 10可正常连接目标MS SQL 2016 SP2服务器
• 该Red Hat 8服务器能正常连接其他带自签名证书的MS SQL Server
• 目标服务器原本无证书，安装证书后问题仍未解决

解决思路 #

网络层面排查 #

• 执行telnet server_name 1433或nc -zv server_name 1433确认端口连通性，虽然日志显示socket连接成功，但需排查是否存在数据包丢失或延迟过高的情况
• 检查防火墙/安全组规则：确认Red Hat 8到目标SQL服务器的1433端口双向流量未被拦截，注意目标服务器的出站规则可能与Windows客户端的允许范围不同
• 抓包分析：用tcpdump在Red Hat 8上捕获目标服务器1433端口的流量，对比Windows上的连接数据包，排查握手异常、数据包未响应等问题

驱动配置适配 #

• FreeTDS：指定与SQL 2016匹配的TDS版本（SQL 2016对应TDS 7.3），可在命令中添加-C 7.3，或创建~/.freetds.conf配置文件：

  [server_name]
    host = server_name
    port = 1433
    tds version = 7.3
  

  之后用tsql -S server_name -D db_name -U user_name -P pwd尝试连接
• ODBC Driver 18：添加TrustServerCertificate=YES参数跳过证书验证，修改命令为：

  isql -v -k 'DRIVER={ODBC Driver 18 for SQL Server};SERVER=server_name,1433;DATABASE=db_name;UID=user_name;PWD=pwd;TrustServerCertificate=YES'
  

  同时可尝试降级到ODBC Driver 17，新版本驱动对旧SQL服务器的兼容性可能存在问题

SQL服务器配置检查 #

• 确认目标SQL Server的TCP/IP协议已启用，且监听1433端口（在SQL Server配置管理器中检查）
• 确认SQL Server允许混合身份验证（如果使用SQL账号而非Windows域账号）
• 查看SQL Server的登录日志，检查是否有来自Red Hat 8服务器的登录请求记录，是否存在权限或认证相关的拒绝信息

系统环境适配 #

• 检查Red Hat 8的时间同步：确保Linux服务器与SQL服务器时间差在5分钟以内，避免时间偏差影响认证流程
• 确认FreeTDS和ODBC驱动的依赖库（如glibc、openssl）安装完整，版本符合驱动要求

内容的提问来源于stack exchange，提问作者Maxim