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Posted 23 June 2014 - 05:44 AM
Posted 23 June 2014 - 07:52 AM
I manage a network. I use the ping command the most... I did have a strange issue a while back with a switch that was getting too hot due to a fan starting to fail (I figured this out after having to reset the switch 3 times in 1 week). I could ping the switch, but I could not login through the web GUI. The strange issue was that no new computer added into the switch could get an IP address from the DHCP server. I could ping the DHCP server from the switch (This is why the issue was strange). New computers added to another switch could get an IP address so I knew the DHCP server was working. I reset the switch and the web gui started working and then new computers could connect as well. I repalced the fans in the switch and no more problems.
Edited by zingo156, 23 June 2014 - 09:24 AM.
Posted 23 June 2014 - 09:04 AM
I'll follow zingo156.
While network support has not been my primary function, it is always a part of my job. Like zingo156 I use the old fashion command prompt for troubleshooting, with PING and IPCONFIG the two major tools. Since I have been supporting IPv4 networks these work fine, I have yet to support a solid IPv6 network yet. Most of the network issues I deal with are client based, computers, printers, and IP phones. Here are the basics:
1. Has it ever worked?
2. How wide spread is the issue (one user/device or more)?
3. How does the issue present (slow network, no network, limited network)?
4. What address is the client using or getting from DHCP (IPCONFIG or look at DNS Server leases)?
5. Is the IP address valid for the network the user is on?
6. Can the user ping from near to far (127.0.0.1, switch IP, router IP near side, router IP far side, web address)?
7. Ping failure tells you where to look and who is responsible.
a. 127.0.0.1 - local machine - local level 2
b. Switch IP - local machine and switch - local level 2 and network operations
c. Router IP near side - switch and router - network operations
d. Router IP far side - router and ISP - network operation and ISP
e. Web Address - Firewall, Router, ISP, and web address - security, network operations, ISP, and web administrator
The above is a general example and responsibilities will vary by organization. The larger the organization the more people or groups that might be involved with any specific issue. The larger or higher priority issues will have more people involved in getting the incident resolved.
Posted 23 June 2014 - 10:16 AM
For network issues I troubleshoot using these tools:
ping - checking if a host is responding
nmap - port scanner t
ipconfig (ifconfig on linux)
tracert, traceroute, or mtr - shows the route that the packets take through the network
I do network administration on windows and linux servers troubleshooting connectivity issues, blocked ports, etc. When debugging a network issue I usually find out if the customer is not able to connect to the server at all or just a single service. Then from that I can run tests to figure out if it is the server, switch, router, or an issue with the customers connection. If the customer is not able to connect to a single service on the server (like email) then I can use tools like nmap to see if the server is listening and responding on the SMTP or POP3 ports.
Posted 24 June 2014 - 09:18 AM
Thanks everyone for your responses very much appreciated.
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