Common port numbers

Trying to put together my a icnd1/2 study guide again.

Which well known ports do you think should be comitted to memory?

I mean there are 1023 of them and not everything is really worth taking note of.

(kind of funny that 666 is still owned by doom)

I'd say just the basic ones that you probably use every day, i.e. DNS, FTP, HTTP, HTTPS, Ping, Telnet, SSH etc. Don't bother with anything more obscure than that; if they bring up something obscure then chances are they'll probably give you the info in the question

I'd say just the basic ones that you probably use every day, i.e. DNS, FTP, HTTP, HTTPS, Ping, Telnet, SSH etc. Don't bother with anything more obscure than that; if they bring up something obscure then chances are they'll probably give you the info in the question

What port does "Ping" use?

I'd say just the basic ones that you probably use every day, i.e. DNS, FTP, HTTP, HTTPS, Ping, Telnet, SSH etc. Don't bother with anything more obscure than that; if they bring up something obscure then chances are they'll probably give you the info in the question

What port does "Ping" use?

Ping is ICMP, it's a layer 3 protocol (part of IP). so no port.

Yes ICMP is in itself a protocol like TCP or UDP so ping doesn't have a TCP or UDP port assignment. But you may well see ICMP in things like access control lists in router configs (permit icmp any any), and they might throw a scenario asking why ping doesn't work between two devices, hence the mention of it in the list. Sorry if I wasn't clear enough in the beginning.

TCP Port Application

20 FTP data channel
21 FTP control channel
23 Telnet
25 SMTP
53 Connection-oriented DNS (resolution is on UDP 53)
80 HTTP
88 Internet Key Exchange (IKE)
110 POP3 (Mail)
135 Windows RPC Endpoint Mapper
137 NetBIOS Name Service
139 NetBIOS session
389 LDAP
443 HTTP/S
445 Common Internet File System/native SMB on
Windows 2000 and higher
636 LDAP over SSL
1433 SQL Server (1434 if your port scanner can do UDP)
1723 PPTP
3268 LDAP to a Windows Global Catalog Server
3389 Remote Desktop Protocol (Windows Terminal Services)


Note this port numbers are the target of criminal hackers using Zenmap or nmap