求助：virt-manager 创建虚拟机无法联网

服务器基础
1

我想使用笔记本上的读卡器，但是驱动只有 5.x 的支持，因此想安装 Ubuntu lts 设置设备直通，但是卡在第一步，虚拟机无法联网。全部默认配置，使用默认的 ‘default’: NAT，但是无法虚拟机内无法联网 :melting_face:。

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有遇到同样问题的吗？ 我还试了 cachyos 上的 virt-manager 默认配置一样无法联网，但是能 ping bing.com 可以 ping 通。

2

cat /etc/resolv.conf 看看。

3

Ubuntu 上好像是被 systemd 管理的

ubuntu@ubuntu:~$ cat /etc/resolv.conf 
# This is /run/systemd/resolve/stub-resolv.conf managed by man:systemd-resolved(8).
# Do not edit.
#
# This file might be symlinked as /etc/resolv.conf. If you're looking at
# /etc/resolv.conf and seeing this text, you have followed the symlink.
#
# This is a dynamic resolv.conf file for connecting local clients to the
# internal DNS stub resolver of systemd-resolved. This file lists all
# configured search domains.
#
# Run "resolvectl status" to see details about the uplink DNS servers
# currently in use.
#
# Third party programs should typically not access this file directly, but only
# through the symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a
# different way, replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.

nameserver 127.0.0.53
options edns0 trust-ad
search .

虽然不能联网但是我可以 ping 通， 貌似是因为虚拟机总是会使用 ipv6

ubuntu@ubuntu:~$ ping bing.com
PING bing.com (150.171.28.10) 56(84) bytes of data.
64 bytes from 150.171.28.10 (150.171.28.10): icmp_seq=1 ttl=109 time=78.3 ms
64 bytes from 150.171.28.10 (150.171.28.10): icmp_seq=2 ttl=109 time=79.5 ms
64 bytes from 150.171.28.10 (150.171.28.10): icmp_seq=3 ttl=109 time=80.2 ms
64 bytes from 150.171.28.10 (150.171.28.10): icmp_seq=4 ttl=109 time=81.2 ms
^C
--- bing.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3005ms
rtt min/avg/max/mdev = 78.288/79.785/81.159/1.045 ms
ubuntu@ubuntu:~$

这是 apt update 的情况，无法工作，我这里运营商并没有 ipv6

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4

那你 resolvectl 看看。

5 
ubuntu@ubuntu:~$ resolvectl status
Global
       Protocols: -LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported
resolv.conf mode: stub

Link 2 (enp1s0)
    Current Scopes: DNS
         Protocols: +DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported
Current DNS Server: 192.168.122.1
       DNS Servers: 192.168.122.1
ubuntu@ubuntu:~$
6

这个地址你 ping 得通吗？dig @192.168.122.1 www.baidu.com 能成功吗？

7

你的 nameserver 为什么是这个？这明显不对啊。

8

systemd-resolved 的监听地址就是这个

10

你试试跑一下命令 nslookup www.163.com

11 
ubuntu@ubuntu-Standard-PC-Q35-ICH9-2009:~$ dig @192.168.122.1 www.baidu.com 

; <<>> DiG 9.18.28-0ubuntu0.22.04.1-Ubuntu <<>> @192.168.122.1 www.baidu.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 43723
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;www.baidu.com.			IN	A

;; ANSWER SECTION:
www.baidu.com.		803	IN	CNAME	www.a.shifen.com.
www.a.shifen.com.	83	IN	A	39.156.70.46
www.a.shifen.com.	83	IN	A	39.156.70.239

;; Query time: 10 msec
;; SERVER: 192.168.122.1#53(192.168.122.1) (UDP)
;; WHEN: Sun Aug 17 18:53:56 CST 2025
;; MSG SIZE  rcvd: 101

返回的 ip 地址是对的

12 
ubuntu@ubuntu-Standard-PC-Q35-ICH9-2009:~$ nslookup www.163.com
Server:		127.0.0.53
Address:	127.0.0.53#53

Non-authoritative answer:
www.163.com	canonical name = www.163.com.163jiasu.com.
www.163.com.163jiasu.com	canonical name = www.163.com.w.kunluncan.com.
Name:	www.163.com.w.kunluncan.com
Address: 36.131.158.240
Name:	www.163.com.w.kunluncan.com
Address: 36.131.158.239
Name:	www.163.com.w.kunluncan.com
Address: 36.131.158.236
Name:	www.163.com.w.kunluncan.com
Address: 36.131.158.235
Name:	www.163.com.w.kunluncan.com
Address: 36.131.158.238
Name:	www.163.com.w.kunluncan.com
Address: 36.131.158.237
Name:	www.163.com.w.kunluncan.com
Address: 36.131.158.241
Name:	www.163.com.w.kunluncan.com
Address: 36.131.158.234
Name:	www.163.com.w.kunluncan.com
Address: 2409:8c15:2811:100c:103::7fa
Name:	www.163.com.w.kunluncan.com
Address: 2409:8c15:2811:100c:103::7fb

我这里根本没有 ipv6，但是会返回 ipv6，而且 ipv6 已经被我在设置里禁用掉了

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宿主机器也是这样的

┬─[cattial@cachyos:~]─[19 时 01 分 37 秒]
╰─>$ nslookup www.163.com
Server:         127.0.0.53
Address:        127.0.0.53#53

Non-authoritative answer:
www.163.com     canonical name = www.163.com.163jiasu.com.
www.163.com.163jiasu.com        canonical name = www.163.com.w.kunluncan.com.
Name:   www.163.com.w.kunluncan.com
Address: 36.131.158.235
Name:   www.163.com.w.kunluncan.com
Address: 36.131.158.240
Name:   www.163.com.w.kunluncan.com
Address: 36.131.158.239
Name:   www.163.com.w.kunluncan.com
Address: 36.131.158.236
Name:   www.163.com.w.kunluncan.com
Address: 36.131.158.237
Name:   www.163.com.w.kunluncan.com
Address: 36.131.158.234
Name:   www.163.com.w.kunluncan.com
Address: 36.131.158.241
Name:   www.163.com.w.kunluncan.com
Address: 36.131.158.238
Name:   www.163.com.w.kunluncan.com
Address: 2409:8c15:2811:100c:103::7fb
Name:   www.163.com.w.kunluncan.com
Address: 2409:8c15:2811:100c:103::7fa

不知道为什么虚拟机里面会优先使用 ipv6，比如说在使用 apt 时

buntu@ubuntu-Standard-PC-Q35-ICH9-2009:~$ sudo apt update
[sudo] password for ubuntu: 
0% [Connecting to cn.archive.ubuntu.com (2403:2c80:5::6)] [Connecting to security
13

它觉得你的 IPv6 是通的（而且确实通向某个地方了），看看 ip -6 a 和 ip -6 r。
可以修改 /etc/gai.conf 让 IPv4 优先。

14

应该是默认的安装脚本的问题，我在这里 archlinux bbs 找到了解决方法

tldr

echo firewall_backend=iptables >> /etc/libvirt/network.conf

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15

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