crontab的怪异现象，不能连接daytime服务

[yfish]

我想通过daytime得到另外一台主机的时间，使用这个命令：

# echo "`telnet 192.168.4.27 13 2>&1 `"
Trying 192.168.4.27...
Connected to 192.168.4.27.
Escape character is '^]'.
Mon Sep 15 16:46:34 2003
Connection closed by foreign host.

执行很正常，但我把这一句加到crobtab里就不行了
/etc/crobtab:
... ...
* * * * * root echo "`telnet 192.168.4.27 13 2>&1 `" >>/var/log/timesync.log


/var/log/timesync.log:
Trying 192.168.4.27...
Connected to 192.168.4.27.
Escape character is '^]'.
Connection closed by foreign host.
Trying 192.168.4.27...
Connected to 192.168.4.27.
Escape character is '^]'.
Connection closed by foreign host.
Trying 192.168.4.27...
Connected to 192.168.4.27.
Escape character is '^]'.
Connection closed by foreign host.
... ...


没有时间输出了，这是为什么？

[yfish]

我我发现只要打开tcpdump（tcpdump -X "host 192.168.4.27"），上面的输出就正确了
Trying 192.168.4.27...
Connected to 192.168.4.27.
Escape character is '^]'.
Mon Sep 15 17:11:43 2003
Connection closed by foreign host.

[yfish]

我发现只要打开tcpdump（）tcpdump -X "host 192.168.4.27"，上面的输出就正确了

[yfish]

可能是telnet的bug,也可能是crobtab的问题

[踏岸寻柳]

不要这样：echo "`telnet 192.168.4.27 13 2>&1 `"

试一试这样：telnet 192.168.4.27 13 1>>/var/log/timesync.log 2>>&1