AIX网络诊断及解决现场实例

问题：有两台aix的测试机器，一台做应用，一台做数据库，都在同一个网段下（无双机），其中应用网络没有问题，而数据库这台网络有问题，内网下载只有30几K。
解决方法：对比法
由于这两台机器属于同一网段，机型完全一样，可以将两台机器的网络设置进行细致的对比，看看有何差异，然后改之。

使用netstat -v ent0 | grep -p "Specific Statistics"命令分别查看两台机器
应用：
netstat -v ent0 | grep -p "Specific Statistics"
10/100 Mbps Ethernet PCI Adapter II (1410ff01) Specific Statistics:
--------------------------------------------------------------------
Link Status: Up
Media Speed Selected: Auto negotiation
Media Speed Running: 100 Mbps Full Duplex
Receive Pool Buffer Size: 1024
Free Receive Pool Buffers: 1024
No Receive Pool Buffer Errors: 0
Receive Buffer Too Small Errors: 0
Entries to transmit timeout routine: 0
Transmit IPsec packets: 0
Transmit IPsec packets dropped: 0
Receive IPsec packets: 0
Receive IPsec packets dropped: 0
Inbound IPsec SA offload count: 0
Transmit Large Send packets: 0
Transmit Large Send packets dropped: 0
Packets with Transmit collisions:
1 collisions: 0 6 collisions: 0 11 collisions: 0
2 collisions: 0 7 collisions: 0 12 collisions: 0
3 collisions: 0 8 collisions: 0 13 collisions: 0
4 collisions: 0 9 collisions: 0 14 collisions: 0
5 collisions: 0 10 collisions: 0 15 collisions: 0
数据库：
netstat -v ent0 | grep -p "Specific Statistics"
10/100 Mbps Ethernet PCI Adapter II (1410ff01) Specific Statistics:
--------------------------------------------------------------------
Link Status: Up
Media Speed Selected: 100 Mbps Half Duplex
Media Speed Running: 100 Mbps Half Duplex
Receive Pool Buffer Size: 1024
Free Receive Pool Buffers: 1024
No Receive Pool Buffer Errors: 0
Receive Buffer Too Small Errors: 0
Entries to transmit timeout routine: 0
Transmit IPsec packets: 0
Transmit IPsec packets dropped: 0
Receive IPsec packets: 0
Receive IPsec packets dropped: 0
Inbound IPsec SA offload count: 0
Transmit Large Send packets: 0
Transmit Large Send packets dropped: 0
Packets with Transmit collisions:
1 collisions: 233543413 6 collisions: 0 11 collisions: 0
2 collisions: 0 7 collisions: 0 12 collisions: 0
3 collisions: 0 8 collisions: 0 13 collisions: 0
4 collisions: 0 9 collisions: 0 14 collisions: 0
5 collisions: 0 10 collisions: 0 15 collisions: 0

仔细对比发现数据库这台显然是双工模式与应用这台不同，应用的机器是自适应的，运行时是100M全双工模式，而数据库的机器限制为100M半双工模式，现在就是要将数据库这台改成与应用一样

更改双工模式的命令为smitty chgenet
但是在此之前要将需要更改的网卡down掉，以及所有经过此网卡的服务停止

步骤如下：
ifconfig -a
输出：
en0: flags=5e080863,80;
inet 10.100.10.6 netmask 0xffffff00 broadcast 10.100.10.255

再输入：
ifconfig en0 down
ifconfig en0 detach
smitty chgennt

输出：
[Entry Fields]
Ethernet Adapter ent0
Description 10/100 Mbps Ethernet PCI Adapter II (1410ff01)
Status Available
Location 1L-08
Transmit descriptor queue size [512]
Receive descriptor queue size [512]
Software transmit queue size [8192]
Receive buffer pool size [1024]
Media Speed Auto_Negotiation
IPsec Offload no
Enable hardware transmit and receive checksum yes
Enable TCP Large Send Offload no
Enable Link Polling no
Time interval for Link Polling [500]
Enable ALTERNATE ETHERNET address no
ALTERNATE ETHERNET address [0x000000000000]
Apply change to DATABASE only no

更改之后需要重新设置默认网关（原来的会丢失）
smitty tcpip
Minimum Configuration & Startup
输出：
[Entry Fields]
* HOSTNAME [TEST1-CRM-DB-CLS]
* Internet ADDRESS (dotted decimal) [10.100.10.8]
Network MASK (dotted decimal) [255.255.255.0]
* Network INTERFACE en0
NAMESERVER
Internet ADDRESS (dotted decimal) []
DOMAIN Name []
Default Gateway
Address (dotted decimal or symbolic name) [10.100.10.1]
Cost [0]
Do Active Dead Gateway Detection? no
Your CABLE Type N/A
START TCP/IP daemons Now no

最后将网卡启用
ifconfig en0 up
问题得到解决！