Network Troubleshooting

[Manish.mac03]

A single user unable to access the one application, need all the possible steps to fix this, like what to check in user pc, and switch and router ??

can someone help.

[Manish.mac03]

Can some explain the most challenging issues you have ever faced and what an all steps you have done to fix it, may be switching, routing, datacenter any issues.

please describe everything you have troubleshoot??

[balaji.bandi]

First define, what appliation ?

1. what is the source IP

2. what is the destination IP - where the application not able to access

3. what is port application running?

4. what all the devices in the path to reach source IP to destination IP

5. Is source IP able to ping Destination IP ? YES or  NO ?  YES next step - No then does the Source IP able to reach the gateway

6 YES - telnet IP address port (what is the outcome)

7, is the application HTTP based or HTTPS based? (try different browsers?

Like this N number of combination until you get success.

what is the difference between a working device vs not a working device?

[Manish.mac03]

Hi Balaji,

appreciate your response  

It’s one internal company application, (other applications and internet is fine) that he is not able to access and rest all able to access.

First define, what application ?

1. what is the source IP : Internal company application (any private ip- 10.0.0.0/24 network)

2. what is the destination IP - where the application not able to access : At any branch location and the application server hosted in Data center 

3. what is port application running? Port number is correct

4. what all the devices in the path to reach source IP to destination IP :  PC> Switch L2-> RouterL3> ISP network > Datacenter 

5. Is source IP able to ping Destination IP ? YES or  NO ?  YES next step - No then does the Source IP able to reach the gateway – Able to reach to the gateway

6 YES - telnet IP address port (what is the outcome) : Telent the gateway ip right (if it is router, what to check in router)?

7, is the application HTTP based or HTTPS based? (try different browsers? : HTTPS

Thank You 

MAC

[Georg Pauwen]

Hello,

what application is that anyway, and 'no access' means the user cannot see/open the webpage, or log in ?

What is the difference between this user, and users that CAN access the application, are they on the same hardware/OS ?

[Manish.mac03]

Hello Georg,

User cannot see/open the webpage. (Company one of the internal Application)

The orther users are using same hardware/OS asme as this user.

Thanks

MAC

[balaji.bandi]

what is port application running? Port number is correct
what all the devices in the path to reach source IP to destination IP :  PC> Switch L2-> RouterL3> ISP network > Datacenter

is this issue for only 1 PC ?  how about other devices ?

Can this able to ping that Application Server IP address ?

from DC network can you able to access https application ?

from PC -  (post below output)

ping application-ip

telnet application-ip 443  

[Manish.mac03]

Hi Bala,

is this issue for only 1 PC ? : Yes

how about other devices ? : Working Fine

Can this able to ping that Application Server IP address ? Yes

from DC network can you able to access https application ? Yes it is. (Working fine for other users at the location)

from PC -  (post below output)

ping application-ip  : Able to ping without fail.

telnet application-ip 443  - yes 

Thanks

MAC

[balaji.bandi · Accepted solution]

from PC -  (post below output)

ping application-ip  : Able to ping without fail.

telnet application-ip 443  - yes 

as per the information, Looks like for me browser issue, try a different browser?

can you post what error you getting when you issue https://application-ip  or https://xyz.com (your application FQDN)

Press F12 and check the network (give you some information) - 

[Manish.mac03]

Thanks balaji,

Looks like it was users browser issue, after clean up the browser it is working fine so far.

Thanks 

MAC

[Leo Laohoo]

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@Manish.mac03 wrote:

A single user unable to access the one application

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This is the source and solution to the problem:  ONE SINGLE USER.  

[paul driver]

Hello
Shutdown all applications on that users pc , Then initiate a wireshark capture as you try to establish connection to that specific application, when it fails stop the capture and post the .pcap file

[Manish.mac03]

Thanks Paul,

Looks like it was users browser issue, after clean up the browser it is working fine so far.

Thanks 

MAC

[markanderson]

Basic network troubleshooting steps:

1. Check for local connectivity issues:- The first step in troubleshooting network errors is to check cables, devices, switches, and routers for proper functioning. Teams can also try restarting devices such as the modem, PC, and router to resolve simple network issues. Another issue could be LAN connectivity. To identify and troubleshoot LAN connectivity issues, try to ping the destination IP and check configuration settings and source host.

2. Rectify the duplicate entry of IP address: To check whether the computer is receiving a valid IP address or not, type "ipconfig" in the command prompt. If the IP address starts with 169, it’s receiving an invalid IP.

3. Perform a DNS check: To determine server issues, use command “nslookup.” Results such as refused, timed out or server failure indicate the problem originates from the DNS server of the destination URL.

4. Check malware protection: Check your malware protection tools to ensure they haven't flagged any application, program, or settings affecting network performance.