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I am trying to open a telnet connection from a Wheezy VM to a router in GNS3 but even though the ping is successful, I am unable to open a telnet connection from the VM to any of the routers.

the connectivity is as such : VM > hub > router1

Note : All the comments below have been done after pouring over the internet for an hour. I am no expert on linux , but I have just started with it and loving it.

The output of ps aux | grep telnet shows the service as up and I even installed xinetd which was not initially present in /etc/init.d.

root@debian:/home/debian# ps aux | grep telnet

root 4236 0.0 0.0 3556 780 pts/1 S+ 03:30 0:00 grep telnet

The problems and what I have found

  1. My VM and routers are connected in the same broadcast domain of 192.168.2.0. When I try to telnet from VM to router, connection does not open. When I try to telnet from router to VM on 192.168.2.100 ( eth1 on VM) , it says connection refused.

Here is my route -n and nmap outputs.

root@debian:/home/debian# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         172.20.0.1      0.0.0.0         UG    0      0        0 eth0
169.254.0.0     0.0.0.0         255.255.0.0     U     1000   0        0 eth0
172.20.0.0      0.0.0.0         255.255.252.0   U     0      0        0 eth0
192.168.2.0     0.0.0.0         255.255.255.0   U     0      0        0 eth1

Nmap done: 1 IP address (1 host up) scanned in 3.26 seconds

root@debian:/home/debian# nmap -p 20-23 192.168.2.101

Starting Nmap 6.00 at 2015-12-20 03:37 EST
    Nmap scan report for 192.168.2.101
    Host is up (0.020s latency).
    PORT   STATE    SERVICE
    20/tcp filtered ftp-data
    21/tcp closed   ftp
    22/tcp open     ssh
    23/tcp filtered telnet
MAC Address: C2:01:08:88:00:00 (Unknown)

Nmap done: 1 IP address (1 host up) scanned in 1.54 seconds

So telnet comes up as filtered , and ssh is open.

So , is there some internal ACL filtering the telnet connections where I would have to make some changes in the conf file ?

  1. I have restarted the xinetd , telnetd is also installed , but no service seems to be listening on port 23, which any CISCO router would use for telnet service. However, if i use a port reserved for TCP and being listened to by any service, the connection does open, but doesn't prompt for a login neither produces a banner.

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