Network/Troubleshooting - Revision history

Mbaney at 15:55, 20 February 2025

2025-02-20T15:55:33Z

← Older revision		Revision as of 15:55, 20 February 2025
Line 75:		Line 75:

	==Other Things to consider==		==Other Things to consider==
	*Is your IP address manually set?		* Is your IP address manually set?
	**In order for networking to function properly, a machine must have a unique IP address on its network. In many cases IP address are assigned automatically via the DHCP protocol, but it is also possible to manually set an IP address. If your machine happens to have a manually set IP address that conflicts with that of another host, networking issues may arise.		** In order for networking to function properly, a machine must have a unique IP address on its network. In many cases IP address are assigned automatically via the DHCP protocol, but it is also possible to manually set an IP address. If your machine happens to have a manually set IP address that conflicts with that of another host, networking issues may arise.
	*Are you behind a firewall?		* Are you behind a firewall?
	**Some establishments use firewalls to restrict certain types of traffic both in and out of their networks. If you are having trouble accessing a specific service, this might be the case. To get around this you can connect to the VPN, or use SSH tunneling.		** Some establishments use firewalls to restrict certain types of traffic both in and out of their networks. If you are having trouble accessing a specific service, this might be the case. To get around this you can connect to the VPN, or use SSH tunneling.
	*Other useful commands:		* Other useful commands:
	**<code>dig</code>: performs DNS lookups and displays the answers that are returned from the name server(s) that were queried		** <code>dig</code>: performs DNS lookups and displays the answers that are returned from the name server(s) that were queried
	**<code>host</code>: simple utility for performing DNS lookups		** <code>host</code>: simple utility for performing DNS lookups
	**<code>netstat</code> (macOS/Linux/UNIX): shows network status		** <code>netstat</code> (macOS/Linux/UNIX): shows network status
	**<code>route print</code> (Windows): shows network routing tables		** <code>route print</code> (Windows): shows network routing tables

	==Change your default DNS server==		==Change your default DNS server==
	Please see [[Network/Troubleshooting/DNS \| DNS troubleshooting]] to change your default DNS server.		Please see [[Network/Troubleshooting/DNS \| DNS troubleshooting]] to change your default DNS server.

Mbaney: /* Change your default DNS server */

2023-08-28T15:00:42Z

Change your default DNS server

← Older revision		Revision as of 15:00, 28 August 2023
Line 86:		Line 86:

	==Change your default DNS server==		==Change your default DNS server==
	Please see [[Network/Troubleshooting/DNS \| DNS]] to change your default DNS server.		Please see [[Network/Troubleshooting/DNS \| DNS troubleshooting]] to change your default DNS server.

Mbaney: /* Other Things to consider */

2023-08-28T14:54:17Z

Other Things to consider

← Older revision		Revision as of 14:54, 28 August 2023
Line 80:		Line 80:
	**Some establishments use firewalls to restrict certain types of traffic both in and out of their networks. If you are having trouble accessing a specific service, this might be the case. To get around this you can connect to the VPN, or use SSH tunneling.		**Some establishments use firewalls to restrict certain types of traffic both in and out of their networks. If you are having trouble accessing a specific service, this might be the case. To get around this you can connect to the VPN, or use SSH tunneling.
	*Other useful commands:		*Other useful commands:
	**dig -performs DNS lookups and displays the answers that are returned from the name server(s) that were queried		**<code>dig</code>: performs DNS lookups and displays the answers that are returned from the name server(s) that were queried
	**host -simple utility for performing DNS lookups		**<code>host</code>: simple utility for performing DNS lookups
	**netstat (macOS/Linux/UNIX) -shows network status		**<code>netstat</code> (macOS/Linux/UNIX): shows network status
	**route print (Windows) -shows network routing tables		**<code>route print</code> (Windows): shows network routing tables

	==Change your default DNS server==		==Change your default DNS server==
	Please see [[Network/Troubleshooting/DNS \| DNS]] to change your default DNS server.		Please see [[Network/Troubleshooting/DNS \| DNS]] to change your default DNS server.

Mbaney at 14:53, 28 August 2023

2023-08-28T14:53:19Z

← Older revision		Revision as of 14:53, 28 August 2023
Line 4:		Line 4:
	*Check that the ethernet cable is plugged in or that you are connected to a wireless network.		*Check that the ethernet cable is plugged in or that you are connected to a wireless network.
	*Check that you have an IP address.		*Check that you have an IP address.
	**On Windows: type 'ipconfig /all' into the command prompt		**Windows: type <code>ipconfig /all</code> into the command prompt
	**Linux/UNIX based hosts: type 'ifconfig' into a terminal		**macOS/Linux/UNIX based hosts: type <code>ifconfig -a</code> into a terminal

	==PING==		==PING==
	PING is a network utility that sends ICMP packets to a specified host to test network connectivity.		PING is a network utility that sends ICMP packets to a specified host to test network connectivity.
	*Open up a command prompt~~. Type '~~ping' followed by the hostname or IP address of the host you want to test connectivity to.		*Open up a command prompt / terminal and type <code>ping</code> followed by the hostname or IP address of the host you want to test connectivity to.
	bash$ ping google.com		bash$ ping google.com
	PING google.com (74.125.228.34) 56(84) bytes of data.		PING google.com (74.125.228.34) 56(84) bytes of data.
Line 16:		Line 16:
	64 bytes from iad23s06-in-f2.1e100.net (74.125.228.34): icmp_seq=3 ttl=52 time=4.41 ms		64 bytes from iad23s06-in-f2.1e100.net (74.125.228.34): icmp_seq=3 ttl=52 time=4.41 ms
	64 bytes from iad23s06-in-f2.1e100.net (74.125.228.34): icmp_seq=4 ttl=52 time=4.04 ms		64 bytes from iad23s06-in-f2.1e100.net (74.125.228.34): icmp_seq=4 ttl=52 time=4.04 ms
	*Linux/~~UNIXS~~ may want to add the '-c' flag followed by a number to specify how many times to ping the destination host.		*On Linux/UNIX, you may want to add the <code>-c</code> flag followed by a number to specify how many times to ping the destination host.

	If you are having trouble connecting to UMIACS services we would suggest you test against one of our publicly accessible [[Nexus]] hosts like nexuscml00.umiacs.umd.edu.		If you are having trouble connecting to UMIACS services, we would suggest you test against one of our publicly accessible [[Nexus]] hosts like <code>nexuscml00.umiacs.umd.edu</code> or <code>nexuscfar00.umiacs.umd.edu</code>.

	<pre>		<pre>
Line 52:		Line 52:
	15 4 ms 4 ms 5 ms iad23s06-in-f6.1e100.net [74.125.228.38]		15 4 ms 4 ms 5 ms iad23s06-in-f6.1e100.net [74.125.228.38]
	Trace complete.		Trace complete.
	*Linux/UNIX:		*macOS/Linux/UNIX:
	**In a terminal type 'traceroute' followed by the hostname or IP address of the host you want to test the route to.		**In a terminal type 'traceroute' followed by the hostname or IP address of the host you want to test the route to.
	bash$ traceroute google.com		bash$ traceroute google.com
Line 72:		Line 72:
	13 iad23s07-in-f8.1e100.net (74.125.228.72) 10.798 ms 13.383 ms 7.540 ms		13 iad23s07-in-f8.1e100.net (74.125.228.72) 10.798 ms 13.383 ms 7.540 ms

	Again, if ~~you~~ you are having trouble connecting to UMIACS~~-based hosts~~, ~~please try to tracert/traceroute to a~~ publicly accessible [[Nexus]] host such as <code>nexuscml00.umiacs.umd.edu</code> or <code>nexuscfar00.umiacs.umd.edu</code>.		Again, if you are having trouble connecting to UMIACS services, we would suggest you test against one of our publicly accessible [[Nexus]] host such as <code>nexuscml00.umiacs.umd.edu</code> or <code>nexuscfar00.umiacs.umd.edu</code>.

	==Other Things to consider==		==Other Things to consider==
	*Is your IP address manually set?		*Is your IP address manually set?
	**In order for networking to function properly a machine must have a unique IP address on its network. In many cases IP address are assigned automatically via the DHCP protocol, but it is also possible to manually set an IP address. If your machine happens to have a manually set IP address that conflicts with that of another host, networking issues may arise.		**In order for networking to function properly, a machine must have a unique IP address on its network. In many cases IP address are assigned automatically via the DHCP protocol, but it is also possible to manually set an IP address. If your machine happens to have a manually set IP address that conflicts with that of another host, networking issues may arise.
	*Are you behind a firewall?		*Are you behind a firewall?
	**Some establishments use firewalls to restrict certain types of traffic both in and out of their networks. If you are having trouble accessing a specific service, this might be the case. To get around this you can connect to the VPN, or use SSH tunneling.		**Some establishments use firewalls to restrict certain types of traffic both in and out of their networks. If you are having trouble accessing a specific service, this might be the case. To get around this you can connect to the VPN, or use SSH tunneling.
	*Other useful commands:		*Other useful commands:
	**dig -performs DNS lookups and displays the answers that are returned from the name server(s) that were queried		**dig -performs DNS lookups and displays the answers that are returned from the name server(s) that were queried
	**host -simple utility for performing DNS ~~loookups~~		**host -simple utility for performing DNS lookups
	**netstat (~~linux~~/UNIX) -shows network status		**netstat (macOS/Linux/UNIX) -shows network status
	**route print (Windows) -shows network routing tables		**route print (Windows) -shows network routing tables

	==Change your default DNS server==		==Change your default DNS server==
	Please see [[Network/Troubleshooting/DNS \| DNS]] to change your default DNS server.		Please see [[Network/Troubleshooting/DNS \| DNS]] to change your default DNS server.

Jayid07: /* Trace Route */

2022-04-22T23:02:56Z

Trace Route

← Older revision		Revision as of 23:02, 22 April 2022
Line 72:		Line 72:
	13 iad23s07-in-f8.1e100.net (74.125.228.72) 10.798 ms 13.383 ms 7.540 ms		13 iad23s07-in-f8.1e100.net (74.125.228.72) 10.798 ms 13.383 ms 7.540 ms

	Again, if you you are having trouble connecting to UMIACS-based hosts, please try to tracert/traceroute to a publicly accessible host such as <code>~~openlab~~.umiacs.umd.edu</code>.		Again, if you you are having trouble connecting to UMIACS-based hosts, please try to tracert/traceroute to a publicly accessible [[Nexus]] host such as <code>nexuscml00.umiacs.umd.edu</code> or <code>nexuscfar00.umiacs.umd.edu</code>.

	==Other Things to consider==		==Other Things to consider==

Jayid07: /* PING */

2022-04-22T23:01:55Z

PING

← Older revision		Revision as of 23:01, 22 April 2022
Line 18:		Line 18:
	*Linux/UNIXS may want to add the '-c' flag followed by a number to specify how many times to ping the destination host.		*Linux/UNIXS may want to add the '-c' flag followed by a number to specify how many times to ping the destination host.

	If you are having trouble connecting to UMIACS services we would suggest you test against one of our publicly accessible ~~hosts like the~~ [[Nexus]] ~~nodes~~.		If you are having trouble connecting to UMIACS services we would suggest you test against one of our publicly accessible [[Nexus]] hosts like nexuscml00.umiacs.umd.edu.

	<pre>		<pre>

Jayid07: /* PING */

2022-04-22T23:00:48Z

PING

← Older revision		Revision as of 23:00, 22 April 2022
Line 18:		Line 18:
	*Linux/UNIXS may want to add the '-c' flag followed by a number to specify how many times to ping the destination host.		*Linux/UNIXS may want to add the '-c' flag followed by a number to specify how many times to ping the destination host.

	If you are having trouble connecting to UMIACS services we would suggest you test against one of our publicly accessible hosts like ~~<code>openlab.umiacs.umd.edu</code>~~.		If you are having trouble connecting to UMIACS services we would suggest you test against one of our publicly accessible hosts like the [[Nexus]] nodes.

	<pre>		<pre>
	$ ping ~~openlab~~.umiacs.umd.edu		-bash-4.2$ ping nexuscml00.umiacs.umd.edu
	PING ~~openlab~~.umiacs.~~umd~~.~~edu~~ (128.8.~~132~~.~~250~~) 56(84) bytes of data.		PING nexuscml00.umiacs.UMD.EDU (128.8.121.4) 56(84) bytes of data.
	64 bytes from ~~opensub02~~.umiacs.umd.edu (128.8.~~132~~.~~250~~): icmp_seq=1 ttl=52 time=14.1 ms		64 bytes from nexuscml00.umiacs.umd.edu (128.8.121.4): icmp_seq=1 ttl=60 time=0.507 ms
	64 bytes from ~~opensub02~~.umiacs.umd.edu (128.8.~~132~~.~~250~~): icmp_seq=2 ttl=52 time=16.3 ms		64 bytes from nexuscml00.umiacs.umd.edu (128.8.121.4): icmp_seq=2 ttl=60 time=0.335 ms
	64 bytes from ~~opensub02~~.umiacs.umd.edu (128.8.~~132~~.~~250~~): icmp_seq=3 ttl=52 time=19.5 ms		64 bytes from nexuscml00.umiacs.umd.edu (128.8.121.4): icmp_seq=3 ttl=60 time=0.328 ms
	64 bytes from ~~opensub02~~.umiacs.umd.edu (128.8.~~132~~.~~250~~): icmp_seq=4 ttl=52 time=12.4 ms		64 bytes from nexuscml00.umiacs.umd.edu (128.8.121.4): icmp_seq=4 ttl=60 time=0.379 ms
	</pre>		</pre>

Mbaney: /* Trace Route */

2020-05-13T17:22:13Z

Trace Route

← Older revision		Revision as of 17:22, 13 May 2020
Line 72:		Line 72:
	13 iad23s07-in-f8.1e100.net (74.125.228.72) 10.798 ms 13.383 ms 7.540 ms		13 iad23s07-in-f8.1e100.net (74.125.228.72) 10.798 ms 13.383 ms 7.540 ms

	Again if you you are having trouble connecting to UMIACS based hosts please try to traceroute to a publicly accessible host such as <code>openlab.umiacs.umd.edu</code>.		Again, if you you are having trouble connecting to UMIACS-based hosts, please try to tracert/traceroute to a publicly accessible host such as <code>openlab.umiacs.umd.edu</code>.

	==Other Things to consider==		==Other Things to consider==

Derek: /* Trace Route */

2020-05-13T14:03:19Z

Trace Route

← Older revision		Revision as of 14:03, 13 May 2020
Line 73:		Line 73:

	Again if you you are having trouble connecting to UMIACS based hosts please try to traceroute to a publicly accessible host such as <code>openlab.umiacs.umd.edu</code>.		Again if you you are having trouble connecting to UMIACS based hosts please try to traceroute to a publicly accessible host such as <code>openlab.umiacs.umd.edu</code>.

	* Linux/Unix
	** <code>traceroute openlab.umiacs.umd.edu</code>
	* Windows

	==Other Things to consider==		==Other Things to consider==

Derek at 14:03, 13 May 2020

2020-05-13T14:03:04Z

@@ Line 17: / Line 17: @@
 bytes from iad23s06-in-f2.1e100.net (74.125.228.34): icmp_seq=4 ttl=52 time=4.04 ms
 *Linux/UNIXS may want to add the '-c' flag followed by a number to specify how many times to ping the destination host.
 ==Trace Route==
@@ Line 60: / Line 71: @@
   72.14.238.247 (72.14.238.247)  7.823 ms  7.616 ms  8.331 ms
   iad23s07-in-f8.1e100.net (74.125.228.72)  10.798 ms  13.383 ms  7.540 ms
 ==Other Things to consider==