两台Ubuntu 22.04主机无法通过Samba互访问题求助

大家好，我遇到了一个Samba跨主机互访的问题，折腾了好几种方法都没解决，想请各位帮忙排查下：

环境说明 #

• 两台主机都是Ubuntu 22.04.2 LTS x86_64，全程没有Windows机器参与
• 两台都运行着Samba服务，版本为：smbd version 4.15.13-Ubuntu
• 为了排除安全限制干扰，我已经关闭了网络上所有安全策略，允许所有流量通行

问题现象 #

不管在哪台机器上打开文件管理器，进入「其他位置」的网络板块，都能看到本地和另一台主机的Samba服务。访问本地的Samba共享完全没问题，但尝试连接另一台主机的共享时，总会弹出错误提示：

"Unable to access location"
"Failed to retrieve share list from server: Connection timed out"

我试过冷启动两台机器、修改工作组名称等方法，但都没用，始终只能访问本地共享，远程连接一直超时。

我的Samba配置文件 #

smb.conf内容：

[global]
server string = SYSTEM-1
workgroup = INVESTIGATIONS
security = user
map to guest = Bad User
name resolve order = bcast host
include = /etc/samba/shares.conf

shares.conf内容：

[Uploads]
path = /share/Uploads
force user = smbuser
force group = smbgroup
create mask = 0664
force create mode = 0664
directory mask = 0775
force directory mode = 0775
public = yes
writeable = yes

[Downloads]
path = /share/Downloads
force user = smbuser
force group = smbgroup
create mask = 0664
force create mode = 0664
directory mask = 0775
force directory mode = 0775
public = yes
writeable = no

备注：内容来源于stack exchange，提问作者Ted Montana