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1500 questions
16
votes
2 answers
What is this device used by a networking technology company?
I recently saw two men open up the sidewalk in a major German city. It seemed they dug out this device
Both men worked for a networking technology company, so I hope this is on topic here.
What is this device?
Stefan
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16
votes
5 answers
How can I reset a VPN tunnel on a Cisco ASA?
On a site-to-site VPN using a ASA 5520 and 5540, respectively, I noticed that from time to time traffic doesn't pass any more, sometimes just there's even missing traffic just for one specific traffic selection / ACL while other traffic over the…
Stefan
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16
votes
2 answers
Router won't hold configuration
I have reset the password on a Cisco 1700 router, now when I copy run start or write mem then reload or reboot, it defaults to factory settings, i.e. it is not holding the configuration I have just written.
To reset the password I used the boot from…
Andy Mac
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- 6
16
votes
4 answers
Why is 10.1.255.255 an invalid broadcast address?
I’ve been following the CCENT official certification book(100-105) and came upon this question in the “do I know this already?” quiz. The books only covered /24 subnetting only so far.
Which of the following is a network broadcast address?
a.…
Bilal Baroudi
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16
votes
7 answers
Automate configuration backup (every minute) in Cisco IOS
I'd like to make my Cisco router automatically do a copy run TFTP (and populate the fields automatically) every 1 minute. I'd also like it to be run in the background. Anyone know if this is possible/how to do it? I'd like to do this for the sake of…
Michael May
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16
votes
1 answer
Should ARP requests be VLAN tagged?
I'm wondering if the ARP requests should be tagged when being sent out of a VLAN tagged interface?
It seems logical to me that the ARP request should be tagged, since it needs to travel all the broadcast domain. If any switches or devices in the…
Simon
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16
votes
3 answers
Why would a switch be connected to a router using three ethernet cables?
In our rented office, we have a router (BT smart hub) connected to a large switch (model unknown). The two are connected using three ethernet cables, thus:
-----------------------
| 1 2 3 4 Router |
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| | | |
|…
EvilDr
- 273
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16
votes
3 answers
mtr output with high packet loss on one hop
I'm investigating a complaint of poor performance from an end user accessing a site I help maintain.
I have these two mtr outputs to the end user, the first from the site:
Packets Pings
Host …
MikeyB
- 313
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16
votes
3 answers
class-default matches control traffic?
I'm seeing an issue with BFD on a link that's being policed egress where it appears during times where the policer is maxed BFD packets are not getting to the other side. I'm wondering if BFD hellos are subject to the policer or if they fall…
Mud
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- 9
16
votes
3 answers
DWDM active and passive comparison
I am trying to understand the cross-over point for when I would deploy active DWDM over passive DWDM (as active seems to be more expensive based on my initial research);
Passive DWDM takes in various colours / wavelengths and muxes them onto a…
jwbensley
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16
votes
4 answers
Best practice using Cisco's "ip-helper" for DHCP?
Our topology is such that we have two 4510's in our IDF closets. Each switch has a data VLAN and a voice VLAN. The switches are layer 2 trunked to the core, where the VLAN interfaces are, routing happens, and DHCP is forwarded to the DHCP…
Pseudocyber
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16
votes
3 answers
What does logging synchronous command do?
Can somebody describe me what does
logging synchronous
command do ?
Abiral
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16
votes
2 answers
BGP multipath with different ASNs feasible for production networks?
on Cisco (this command is hidden for some reason)
#bgp bestpath as-path multipath-relax
The default BGP behavior only installs only routes with exact the same AS_PATH into RIB. With multipath-relax, the AS_PATH only needs to be of the same length.…
sdaffa23fdsf
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16
votes
5 answers
About the switchport mode
I am new to network Engineering. I find it is hard to distinguish and understand different switchport settings.
Why can I have a switchport set to access, auto, or dynamic? What are they used for? Are those functions only used for a host to switch…
Samuel
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16
votes
5 answers
What causes total output drops on a cisco switch interface?
I have an HP c7000 blade chassis which contains Cisco 3120X and Cisco 3120G switches running ios 12.2(58)SE1. The blades themselves are very lightly loaded yet many interfaces on different blade switches in the chassis show a fairly high number of…
User123456
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