KB: Replace telnet with a python script

On some editor's Linux based appliance(s), there is not telnet binary installed. To test TCP netwotk flows, it's possible to use python's socket module with a short script:

 1#!/usr/bin/python
 2
 3import socket
 4import sys
 5
 6if len(sys.argv) != 3:
 7    print("usage: telnet.py IPADDRESS PORT")
 8    exit(-1)
 9
10print("Opening connection on %s port %s" % (sys.argv[1], sys.argv[2]))
11
12try:
13    conn=socket.create_connection((sys.argv[1],sys.argv[2]),timeout=30)
14except socket.timeout:
15    print("Connection error: timeout")
16    exit(-1)
17except:
18    print("Connection error: unknown")
19    exit(-1)
20print("Connection succeed")
21exit(0)

Usage:

1$ python telnet.py
2usage: telnet.py IPADDRESS PORT

✅ Successful test:

1$ python telnet.py 10.10.10.10 443
2Opening connection on 10.10.10.10 port 443
3Connection succeed

❌ Failed test:

1$ python telnet.py 10.10.10.10 10443
2Opening connection on 10.10.10.10 port 10443
3Connection error: unknown