linux遇到的问题

1.问题：ssh 时候，出现22端口，refused!

原因：很可能是22端口开，即是sshd服务没有启动。

解决：/etc/init.d/sshd
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2.问题：
[root@localhost ~]# scp /usr/alen 10.1.29.15:/usr/alen
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
72:e0:a1:b1:d5:83:c6:4d:33:28:8c:0a:e5:f4:74:c0.
Please contact your system administrator.
Add correct host key in /root/.ssh/known_hosts to get rid of this message.
Offending key in /root/.ssh/known_hosts:2
RSA host key for 10.1.29.15 has changed and you have requested strict checking.
Host key verification failed.

原因：RSA有问题
解决：将本地~/.ssh/known_hostsh中相对应的ip等信息删除掉，主要是因为我使用不同的系统，但是ip相同，导致RSA host key改变
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3.yum install gcc
Error: Missing Dependency: /usr/lib/gcc/i386-neoshine-linux/4.1.1/libgcj.spec is needed by package java-1.4.2-gcj-compat-src-1.4.2.0-40jpp.115.ns5.4.02.i386 (installed)
Error: Missing Dependency: /usr/lib/gcc/i386-neoshine-linux/4.1.1/libgcj.spec is needed by package java-1.4.2-gcj-compat-devel-1.4.2.0-40jpp.115.ns5.4.02.i386 (installed)
 You could try using --skip-broken to work around the problem
 You could try running: package-cleanup --problems
                        package-cleanup --dupes
                        rpm -Va --nofiles --nodigest
The program package-cleanup is found in the yum-utils package.

原因：使用的是中标麒麟linux server版本，使用的是yum源有问题
解决：配置yum源,vim /etc/yum.repos.d/ns5.repo  ，源可以从网上搜索一个覆盖那文件内容即可.