Fixing "EAI_NONAME" Error in FileZilla – DNS Resolution Failure

Table of Contents: Introduction Test DNS Resolution Use IP Address in FileZilla Fix DNS Issues Check Firewall & Network Use Passive Mode Final Summary

The EAI_NONAME - Neither nodename nor servname provided, or not known error in FileZilla FTP Client occurs when the FTP hostname cannot be resolved to an IP address. This means your DNS settings are incorrect, outdated, or misconfigured.

In this guide, we'll troubleshoot and fix DNS resolution failure for FileZilla step by step.

Test DNS Resolution in Command Prompt or Terminal

Before changing settings, test if your DNS can resolve the FTP hostname.

Test DNS Resolution in Windows

1. Open Command Prompt:
   • Press Win + R, type cmd, and press Enter.
2. Run the nslookup command:

   nslookup ftp.yourdomain.com

   Expected Output:

   Server:  google-public-dns-a.google.com
   Address:  8.8.8.8
   
   Name:    ftp.yourdomain.com
   Address:  192.168.1.10

   If you see:

   *** dns server can't find ftp.yourdomain.com: NXDOMAIN

   This means DNS is not resolving the FTP hostname correctly.

Test DNS Resolution in Linux/macOS

Use the dig or host command:

Using dig:

dig ftp.yourdomain.com

Expected Output:

;; ANSWER SECTION:
ftp.yourdomain.com.  300  IN  A  192.168.1.10

If you see "NO ANSWER" or "NXDOMAIN", DNS is not resolving properly.

Using host:

host ftp.yourdomain.com

If the result returns an IP address, DNS is working.
If it says "Host not found," DNS is failing.

Use IP Address Instead of Hostname in FileZilla

If DNS is failing, try connecting with an IP address instead of a hostname.

1. Open FileZilla
2. Click on File > Site Manager
3. Select your FTP site
4. Change "Host" from ftp.yourdomain.com to 192.168.1.10 (your FTP server's IP address)
5. Click Connect

If the connection works, the issue is with DNS.
If the connection still fails, move to the next step.

Fix DNS Issues

Flush DNS Cache

If your computer is using an outdated DNS cache, clearing it can fix the issue.

Windows:

ipconfig /flushdns

macOS:

sudo killall -HUP mDNSResponder

Linux (systemd-based distros like Ubuntu, Debian, CentOS 8+):

systemd-resolve --flush-caches

Now restart FileZilla and try connecting again.

Add FTP Server to the Hosts File

If DNS is not resolving correctly, manually add the FTP server to your hosts file.

Windows:

1. Open Notepad as Administrator
   • Click Start, type Notepad, right-click Notepad, and select Run as administrator.
2. Open the hosts file
   • Click File > Open
   • Navigate to: C:\Windows\System32\drivers\etc\hosts
   • Select "All Files" and open hosts.
3. Add the FTP Server Entry
   • Add this line at the bottom: 192.168.1.10 ftp.yourdomain.com
   • Save the file.

Now, FileZilla should recognize the hostname.

Linux/macOS:

1. Open the terminal and edit the hosts file:

   sudo nano /etc/hosts

2. Add this line:

   192.168.1.10 ftp.yourdomain.com

3. Save and exit.

Now retry connecting in FileZilla.

Change DNS Servers to Google or Cloudflare

If DNS resolution still fails, use a public DNS server like Google or Cloudflare.

Change DNS on Windows

1. Open Control Panel > Network and Internet > Network and Sharing Center
2. Click Change adapter settings
3. Right-click your active connection (WiFi or Ethernet) > Properties
4. Click on Internet Protocol Version 4 (TCP/IPv4) > Properties
5. Select Use the following DNS server addresses and enter:
   • Preferred DNS server: 8.8.8.8
   • Alternate DNS server: 8.8.4.4
6. Click OK and restart your connection.

Change DNS on Linux

Edit the resolv.conf file:

sudo nano /etc/resolv.conf

Add:

nameserver 8.8.8.8
nameserver 8.8.4.4

Save and restart networking:

systemctl restart networking

Now retry your FileZilla connection.

Check Your Firewall & Network Settings

If DNS is working but FTP still won’t connect, check your firewall settings.

Allow FTP in Windows Firewall

1. Open Control Panel > Windows Defender Firewall
2. Click "Allow an app or feature through Windows Defender Firewall"
3. Find FileZilla Client and ensure it's allowed for both Private and Public networks
4. Click OK

Restart FileZilla and try connecting.

Allow FTP Ports on Linux

If using UFW (Ubuntu/Debian):

sudo ufw allow 21/tcp
sudo ufw allow 20/tcp
sudo ufw allow 990/tcp
sudo ufw reload

If using Firewalld (CentOS/RHEL):

sudo firewall-cmd --add-service=ftp --permanent
sudo firewall-cmd --add-port=990/tcp --permanent
sudo firewall-cmd --reload

Now FileZilla should be able to connect.

Use Passive Mode in FileZilla

Some networks block Active FTP mode. Switch to Passive Mode:

1. Open FileZilla
2. Go to Edit > Settings
3. Under Connection > FTP, select Passive (Recommended)
4. Click OK and try connecting

Passive mode helps bypass firewall and NAT issues.

Final Troubleshooting Summary

Now FileZilla should connect without the EAI_NONAME error!