网络服务基础 - TCP_wrappers(简单防火墙)

野性酷女 2022-01-05 09:45 155阅读 0赞

## 1.概念 ##

相比较于iptables来说，TCP\_wrappers只对个别的TCP的特定服务起安全监测和访问控制的作用。  
鉴别方法就是看该服务，是否调用libwrap.so库文件。  
![在这里插入图片描述][20190623174614269.png]

## 2.判断方式 ##

![在这里插入图片描述][20190623174805765.png]  
**举例**

[root@oracle ~]# which sshd         
    /usr/sbin/sshd
    [root@oracle ~]# ldd /usr/sbin/sshd  
            linux-vdso.so.1 =>  (0x00007ffe605ae000)
            libfipscheck.so.1 => /lib64/libfipscheck.so.1 (0x00007f4ca7ee6000)
            libwrap.so.0 => /lib64/libwrap.so.0 (0x00007f4ca7cdb000)
            libaudit.so.1 => /lib64/libaudit.so.1 (0x00007f4ca7ab6000)
            libpam.so.0 => /lib64/libpam.so.0 (0x00007f4ca78a8000)
            libdl.so.2 => /lib64/libdl.so.2 (0x00007f4ca76a4000)
            libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f4ca7484000)
            libcrypto.so.10 => /usr/lib64/libcrypto.so.10 (0x00007f4ca70a0000)
            libutil.so.1 => /lib64/libutil.so.1 (0x00007f4ca6e9d000)
            libz.so.1 => /lib64/libz.so.1 (0x00007f4ca6c86000)
            libnsl.so.1 => /lib64/libnsl.so.1 (0x00007f4ca6a6d000)
            libcrypt.so.1 => /lib64/libcrypt.so.1 (0x00007f4ca6836000)
            libresolv.so.2 => /lib64/libresolv.so.2 (0x00007f4ca661b000)
            libgssapi_krb5.so.2 => /lib64/libgssapi_krb5.so.2 (0x00007f4ca63d7000)
            libkrb5.so.3 => /lib64/libkrb5.so.3 (0x00007f4ca60f0000)
            libk5crypto.so.3 => /lib64/libk5crypto.so.3 (0x00007f4ca5ec3000)
            libcom_err.so.2 => /lib64/libcom_err.so.2 (0x00007f4ca5cbf000)
            libnss3.so => /usr/lib64/libnss3.so (0x00007f4ca597f000)
            libc.so.6 => /lib64/libc.so.6 (0x00007f4ca55ea000)
            /lib64/ld-linux-x86-64.so.2 (0x0000003bd0c00000)
            libfreebl3.so => /lib64/libfreebl3.so (0x00007f4ca53e7000)
            libkrb5support.so.0 => /lib64/libkrb5support.so.0 (0x00007f4ca51db000)
            libkeyutils.so.1 => /lib64/libkeyutils.so.1 (0x00007f4ca4fd8000)
            libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f4ca4dbb000)
            libnssutil3.so => /usr/lib64/libnssutil3.so (0x00007f4ca4b8e000)
            libplc4.so => /lib64/libplc4.so (0x00007f4ca4989000)
            libplds4.so => /lib64/libplds4.so (0x00007f4ca4785000)
            libnspr4.so => /lib64/libnspr4.so (0x00007f4ca4546000)
            librt.so.1 => /lib64/librt.so.1 (0x00007f4ca433e000)
    [root@oracle ~]# ldd /usr/sbin/sshd | grep libwrap.so
            libwrap.so.0 => /lib64/libwrap.so.0 (0x00007f70b6bef000)
    [root@oracle ~]#

## 3.工作原理 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjE5MzQ4OQ_size_16_color_FFFFFF_t_70]  
4.TCP Wrappers的使用  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjE5MzQ4OQ_size_16_color_FFFFFF_t_70 1]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjE5MzQ4OQ_size_16_color_FFFFFF_t_70 2]

[20190623174614269.png]: /images/20211229/b75d0962e919485d93cc25261cc35605.png
[20190623174805765.png]: /images/20211229/e44148fe689740fb9c4801fd72984a30.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjE5MzQ4OQ_size_16_color_FFFFFF_t_70]: /images/20211229/755ada800fe349a484da797b00733af5.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjE5MzQ4OQ_size_16_color_FFFFFF_t_70 1]: /images/20211229/2ca143098b7a41eea04157c1bd1e8297.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjE5MzQ4OQ_size_16_color_FFFFFF_t_70 2]: /images/20211229/76a92d0cfa2f41ac805eceda13a3d291.png