Many Linux administrators encounter the frustrating scenario where Windows SMB shares mounted on Linux servers periodically disconnect with the cryptic error:

kernel: CIFS VFS: BAD_NETWORK_NAME: \\\\servername\\folder

This typically happens with configurations like:

//servername/folder /localfolder cifs credentials=/login.txt,x-systemd.automount,
x-systemd.device-timeout=5,_netdev,noserverino,noperm,sec=ntlmssp,vers=3.0 0 0

The x-systemd.automount option doesn't always handle SMB reconnections perfectly. Here are more robust alternatives:

//servername/folder /localfolder cifs credentials=/login.txt,_netdev,auto,
soft,timeo=30,retrans=3,noserverino,noperm,sec=ntlmssp,vers=3.0 0 0

Key improvements:

• soft mount instead of hard mount
• Explicit timeo and retrans values
• Removed problematic systemd options

Create /usr/local/bin/check_mount.sh:

#!/bin/bash

MOUNT_POINT="/localfolder"
SHARE="//servername/folder"

if ! mountpoint -q "$MOUNT_POINT"; then
    logger "CIFS mount not present, attempting remount"
    mount $MOUNT_POINT
    if [ $? -ne 0 ]; then
        umount -l $MOUNT_POINT
        mount $MOUNT_POINT
    fi
fi

Add to cron (crontab -e):

*/5 * * * * /usr/local/bin/check_mount.sh

For more stable connections, try these additional options:

vers=3.1.1,cache=strict,rsize=65536,wsize=65536,actimeo=30

Explanation of critical parameters:

• cache=strict: Better caching behavior
• rsize/wsize: Optimized for modern networks
• actimeo: Reduced attribute cache timeout

Install debugging tools:

sudo apt install cifs-utils

Check connection status:

sudo smbstatus

Enable detailed logging:

echo 7 > /proc/fs/cifs/cifsFYI

View logs:

dmesg | grep CIFS

---

Many Linux administrators encounter unstable CIFS mounts when connecting to Windows SMB shares. The BAD_NETWORK_NAME error typically indicates one of several potential issues:

• Network connectivity interruptions
• Server-side share configuration changes
• Authentication token expiration
• Incomplete mount options

Your current fstab entry:

//servername/folder /localfolder cifs credentials=/login.txt,x-systemd.automount,
x-systemd.device-timeout=5,_netdev,noserverino,noperm,sec=ntlmssp,vers=3.0 0 0

While generally correct, let's enhance this configuration for better resilience:

Consider these additional parameters:

//fileserver/shared /mnt/share cifs credentials=/etc/cifs.creds,uid=1000,gid=1000,
file_mode=0770,dir_mode=0770,vers=3.1.1,_netdev,nofail,hard,rsize=65536,
wsize=65536,cache=none,user_xattr,noserverino,sec=ntlmssp 0 0

Key improvements:

• nofail: Prevents boot failures
• hard: Persistent retries on failures
• vers=3.1.1: Explicit SMB version
• cache=none: Reduces caching issues

Create a monitoring script (/usr/local/bin/check_cifs.sh):

#!/bin/bash

MOUNT_POINT="/mnt/share"
SERVER="fileserver"

if ! mountpoint -q "$MOUNT_POINT"; then
    logger "CIFS mount not present, attempting remount"
    umount -l "$MOUNT_POINT" 2>/dev/null
    mount "$MOUNT_POINT" && logger "CIFS remount successful"
fi

# Verify actual connectivity
if timeout 5 smbclient -U user //$SERVER/shared -c "ls" &>/dev/null; then
    if ! timeout 5 ls "$MOUNT_POINT" &>/dev/null; then
        logger "CIFS stale mount detected, forcing remount"
        umount -l "$MOUNT_POINT"
        mount "$MOUNT_POINT"
    fi
fi

Create /etc/systemd/system/cifs-monitor.service:

[Unit]
Description=CIFS Mount Monitor
After=network.target

[Service]
Type=oneshot
ExecStart=/usr/local/bin/check_cifs.sh

And a timer unit /etc/systemd/system/cifs-monitor.timer:

[Unit]
Description=Run CIFS mount check every 5 minutes

[Timer]
OnBootSec=5min
OnUnitActiveSec=5min

[Install]  
WantedBy=timers.target

When issues occur, collect these diagnostics:

# Check current SMB connections
sudo smbstatus

# View detailed CIFS debugging
echo 7 | sudo tee /proc/fs/cifs/cifsFYI

# Network connectivity test
sudo smbclient -L //servername -U username -d3