Ubuntu 14.04 中缺少网络环回设备

Ubuntu 14.04 中缺少网络环回设备

我想通过 JTAG 编程 FPGA,xmd 脚本连接到 127.0.0.1:3121 来执行此操作。几个月来,这个工作一直很好。重新启动后,这个连接突然不再存在,我也无法再 ping 127.0.0.1 或 localhost(仍然解析为 127.0.0.1)。ifconfig 缺少“lo”。我有 eth4 和 eth5(我的两个网卡)的条目,但没有 lo。完整输出在问题的末尾。与其他计算机的连接工作正常。我如何让它再次运行?

我尝试手动启动它但没有任何改变:

> ifup lo
ifup: interface lo already configured

> ifup --force lo  
(no output)

这也不起作用:

> route add -host 127.0.0.1 dev lo  
SIOCADDRT: No such device

一些诊断输出:

> route -n  
Kernel IP routing table  
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface  
0.0.0.0         192.168.153.1   0.0.0.0         UG    0      0        0 eth5  
192.168.10.0    0.0.0.0         255.255.255.0   U     1      0        0 eth4  
192.168.153.0   0.0.0.0         255.255.255.0   U     1      0        0 eth5  

> cat /var/run/network/ifstate  
lo=lo

> cat /etc/network/interfaces  
# interfaces(5) file used by ifup(8) and ifdown(8)  
auto lo  
iface lo inet loopback

> iptables -L  
Chain INPUT (policy ACCEPT)  
target     prot opt source               destination           

Chain FORWARD (policy ACCEPT)  
target     prot opt source               destination           

Chain OUTPUT (policy ACCEPT)  
target     prot opt source               destination

我没有 /etc/iptables.conf

我也尝试sudo rm -rf /var/run/network/*这个问题。我照做了apt-get updateapt-get upgrade没有变化。

> ifconfig 127.0.0.1 lo  
lo: Unknown host  
ifconfig: `--help' gives usage information.

ifconfig 的输出:

eth4      Link encap:Ethernet  HWaddr 00:24:e8:45:8f:10    
          inet addr:192.168.10.2  Bcast:192.168.10.255  Mask:255.255.255.0  
          inet6 addr: fe80::224:e8ff:fe45:8f10/64 Scope:Link  
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1  
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0  
          TX packets:67 errors:0 dropped:0 overruns:0 carrier:0  
          collisions:0 txqueuelen:1000   
          RX bytes:0 (0.0 B)  TX bytes:10916 (10.9 KB)  
          Interrupt:21 Memory:f7fe0000-f8000000   

eth5      Link encap:Ethernet  HWaddr d8:eb:97:71:be:e5    
          inet addr:192.168.153.124  Bcast:192.168.153.255  Mask:255.255.255.0  
          inet6 addr: fe80::daeb:97ff:fe71:bee5/64 Scope:Link  
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1  
          RX packets:35392 errors:0 dropped:0 overruns:0 frame:0  
          TX packets:28754 errors:0 dropped:0 overruns:0 carrier:0  
          collisions:0 txqueuelen:1000   
          RX bytes:20734790 (20.7 MB)  TX bytes:4354467 (4.3 MB) 

编辑:

> ip link  
1: ttyUSB0: <LOOPBACK> mtu 65536 qdisc noop state DOWN mode DEFAULT group default  
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00  
2: eth5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000  
link/ether d8:eb:97:71:be:e5 brd ff:ff:ff:ff:ff:ff  
3: eth4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000  
link/ether 00:24:e8:45:8f:10 brd ff:ff:ff:ff:ff:ff 

答案1

丹尼斯:我有以下两句台词/etc/网络/接口已经并ifup lo已尝试过。当我这样做时,我显示“接口 lo 已配置”,或者如果我添加,则什么也没有--force

Ginnungagap 的想法是对的。我可以将 ttyUSB0 从“DOWN”改为“UNKNOWN”:

> sudo ip link set ttyUSB0 up

现在输出是

1: ttyUSB0: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

现在它又能工作了,既能ping 也能对 FPGA 进行编程。

非常感谢。

答案2

尝试将以下行添加到 /etc/network/interfaces:

auto lo
iface lo inet loopback

然后做

ifup lo

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