Member Avatar for prajwol

this is me prajwol .................. i cannot login in telnet sever which shows like this ............ couldn't open to the host, on port 23 connection failed
how can solve this problem???????????????????:confused:

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  • Latest Post Latest Post by donaldoohi

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A short diagnostic summary and practical checks to resolve the “couldn't open to the host, on port 23 — connection failed” message. Common root causes left unspoken in the thread are: no service actually listening, the listening service bound to the wrong interface, a host- or network-level firewall/NAT dropping the packets, or the protocol being intentionally blocked by policies. Telnet’s well-known assignment is TCP port 23. (iana.org)

Server-side verification (examples)

# Linux (modern): check TCP listeners for port 23
ss -ltnp | grep ':23'

# Older Linux/net-tools
sudo netstat -tuln | grep ':23'

# Windows: show listeners and PID
netstat -ano | findstr ":23"

These utilities report listening sockets and associated processes; the PID can be mapped to the service to confirm a telnet daemon is actually bound to port 23. (manpages.debian.org)

Client-side testing (examples)

# Windows PowerShell
Test-NetConnection -ComputerName 192.0.2.10 -Port 23

# Simple TCP connect (netcat / ncat)
ncat -v 192.0.2.10 23

# Port discovery / banner/version check
nmap -p 23 -sV 192.0.2.10

PowerShell’s Test-NetConnection gives a quick TcpTestSucceeded boolean and route info; nmap/ncat give more detail about reachability and service banners. (learn.microsoft.com)

Network-path troubleshooting and hardening
If a listener is present but remote clients time out, a packet capture on the server (for example, tcpdump -n -i any tcp port 23) shows whether SYNs arrive. If SYNs never appear, inspect router NAT/port‑forwarding and upstream filtering; if SYNs arrive but no SYN/ACK is sent, the server firewall or service binding is the likely culprit. Use the OS firewall GUI/PowerShell or the router’s port‑forward rules to permit the traffic. (manpages.debian.org)

Security note and final context
Telnet transmits credentials in clear text and is considered insecure for remote administration; industry guidance is to replace Telnet with SSH or place Telnet only behind strong controls (VPN, ACLs) if absolutely necessary. (docs.redhat.com)

This summary builds on the basics already mentioned by and and adds specific checks (listener, client tests, packet capture and firewall/NAT verification) and secure alternatives.

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Member Avatar for DimaYasny

start telnet server
make sure it listens on port 23
make sure port is open on firewall
make sure the server is reachable remotely at all

Member Avatar for holmes008

I think your telnet feature is off go to the start menu/control panel/programm/turn window feature on or off and on TELNET then you can..Find..(Telnet client & Telnet Server)on it! You haven't specified error yet!

Member Avatar for donaldoohi

the port 23 ,how can i gain access the se port.

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