[S9306-GigabitEthernet2/0/42]dis this
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interface GigabitEthernet2/0/42 原先的为trunk，
port link-type trunk
port trunk allow-pass vlan 2 to 4094
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interface GigabitEthernet2/0/42 现在改为access
undo port trunk allow-pass vlan all
port trunk allow-pass vlan 1
port link-type access
port default vlan 10
使用undo port trunk allow-pass vlan all命令时会将默认的Vlan 1也会undo掉，
所以必须再执行一次port trunk allow-pass vlan 1
或者使用下面的命令也可以：
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interface GigabitEthernet0/0/26 原先的为trunk
port link-type trunk
port trunk allow-pass vlan 2 to 4094
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undo port trunk allow-pass vlan 2 to 4094 先undo掉2-4094
undo port link-type 再undo掉trunk
port link-type access 设置为access
port default vlan 10 设置默认VLAN