Questions tagged [interface]
For questions about a physical or virtual interface on a network device. For instance: Interface configurations, troubleshooting and security.
191
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What is the purpose of a switch routed port?
From my Cisco CCNA documentation:
Routed ports are used for point-to-point links. Connecting WAN routers
and security devices are examples of the use of routed ports. In a
switched network, ...
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4
votes
3
answers
382
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Serial interfaces of router are used nowadays?
I've heard the use of serial interfaces of router is not so common in the current network environment.
But in some exams like CCNA, you can still see questions including the knowledge of serial ...
4
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3
answers
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JunOS, access mode interface asks for a vlan
I'm kinda new to networking so I'm going to do my best to try explain my issue.
The issue that I have is that I want to delete all default configuration for my xe interface.
Current configuration:
...
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5
votes
2
answers
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What's the `line protocol` and `Link`?
When I show a switch interface information, there are line protocol and Link:
Switch-A(config-if)# show interface gigabitethernet 0/3
Gi0/3 up, line protocol is up (connected)
Bridge Port Type: ...
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2
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71
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Configuring routers on Cisco
If I have three routers R1, R2, and R3 that are interlinked, then when configuring, do I have to give the command:
description Link to R2
description Link to R3
when configuring R1?
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4
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1
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490
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Which physical interface would be used to send/receive packets intended for a loopback interface?
Let us say, I have configured the managed router with a loopback addresses -
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0 ...
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0
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2
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186
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Cisco Catalyst pseudo interface?
I think I remember reading somewhere that you could have multiple VLANs assigned to a single interface by way of a pseudo interface. Googling with that vocabulary doesn't return proper results though, ...
- 416
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2
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Cisco ASA 5585X Internal-Data0/1 interface errors
I have noticed on Cisco ASA 5585 (SSP-20) interface error counter going up specially overrun but so far we haven't seen any production impact or issue, error rate is low so its not noticable but would ...
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Is a network interface supposed to have no more than one MAC address?
Is a network interface supposed to have no more than one MAC address?
Since a network interface is free to have more than one IP addresses, is IP address a way of multiplexing MAC address, if a ...
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3
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2
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388
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Do the concepts of IP address and network interface not belong to the same layer?
https://unix.stackexchange.com/a/508065/674
You are confusing the device driver layers and the IP layers of the
stack.
At the IP layer, 127.0.0.1 is just another IP address and treated the
...
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2
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1
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312
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What can an IP address be assigned to?
What can an IP address be assigned to?
A network interface, which is what I thought originally. (I seem to hear a network interface can have multiple IP addresses assigned to it, and if it is true, ...
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147
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Can more than one IP addresses be assigned to the same network interface?
Can more than one IP addresses be assigned to the same network interface?
Is it correct that a network interface can be a physical one or a virtual one?
Thanks.
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2
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2
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Junos[MX]: How to show VPLS instance associated with given subinterface
Suppose I have a subinterface with Vlan-vpls encapsulation, like this one:
admin@router> show configuration interfaces ge-2/1/1
flexible-vlan-tagging;
encapsulation flexible-ethernet-services;
...
- 123
1
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2
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595
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Get DHCP IP with subinterface
Router0 has 1 subinterface on gi0/0 and can't get a ip trough dhcp. Is there something I forgot?
The configs:
Router0(got no ip from dhcp):
interface GigabitEthernet0/0
ip address dhcp
duplex ...
- 15
3
votes
1
answer
146
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DHCP Broadcast on SVI
Think of a dhcp broadcast going through multiple switches. What happens to that broadcast when it reaches the vlan interface (svi)?
- 313
4
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3
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650
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Mgmt Vlan vs other SVI s
Think of a layer 3 switch. Assume that we have a management vlan and a mgmt vlan interface. And we have other svi's on the switch. The question is this. I know that mgmt vlan is for telnet/ssh, simply ...
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2
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1
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349
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Wireless Controller 5520 Creating a dynamic interface
I'm hoping to determine the least intrusive way to configuring my WLC.
I am working through the GUI interface and have created a new dynamic interface
[Controller-> Interfaces]
When I went to ...
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4
votes
3
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2k
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What is responsible for dropping Layer 2 frames that's not addressed to it?
It's my understanding that if a network interface card (NIC) receives a Layer 1 packet, it will extract the Layer 2 frame from it, checks its destination MAC address, and if it is not addressed to it (...
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2
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How does a router know the MTU of a network?
I've done several exercises where you're given the MTU of a net or subnet, but I wonder how routers know the MTU of the nets they're connected. I've learnt that in OSPF protocol this information is ...
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1
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Urgent: how to configure different interface using same ip subnet in asa 5506?
Scenario is in old asa firewall 5505 I have switch port access vlan command in different interface. Just like below:
interface Ethernet0/0
!
interface Ethernet0/1
switchport access vlan 2
!
...
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0
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1
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49
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i cant configure the ip adress and subnetmask ,i only have one router "1941" and 2 pc's
the command line is this :
Router0(config-if)#ip adress 192.168.1.1 255.255.255.0
the error message is :
% Invalid input detected at '^' marker.
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0
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1
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How to create interfaces for CSR 1000v for GRE tunnels?
Well, my idea is to connect to 4 CSR 1000v routers in different VPC (without VPC peering).
I've basically finished with everything with the pre-configuration creating VPCs, subnets IGW, modifying ...
- 145
1
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1
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Multiple Networks on Sonicwall with no access to cisco firewall
The issue im having is that i have 2 networks with 2 internet connections. We now all of a sudden have a POS system handling our network. This system blocks our email and a bunch of pages we use. They ...
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2
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2
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How can two interface communicate between them with different subnet
R1 and R2 are connected with serial cable interface but both of them having different subnet and i know they will not communicate so what are other options two communicate between them without the ...
1
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1
answer
435
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What's the relationship of a Router with its loopback interface in logic?
I have a Router1 with a loopback 0 connected to the Router2:
the interface brief is bellow:
Router1>show ip interface brief
Interface IP-Address OK? Method Status ...
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2
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474
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How to use" Multimode SFP GLC SX MMD" in Cisco Catalyst 2960 S connected LAN and single mode OFC network
We have single mode OFC network and CAT 6 CAT5 LAN with ethernet and gigabit Ethernet switches and ordered for "GE SFP, LC CONNECTOR LX/LH TRANSCEIVER FOR SINGLE MODE FIBER OF CISCO CATALYST 2960 S" ...
1
vote
1
answer
46
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Network Security Tunnel
In the Tunnel Interface, when I edit the tunnel information, it shows:
Attributes Values
Tunnel Source IF10
Tunnel Destination 1.0.0.1
Tunnel Mode GRE
What does IF10 ...
- 11
1
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2
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How to assign all interfaces in one router to OSPF backbone area?
Is there any command to assign all interfaces in router (CISCO 2691) to OSPF backbone area? I was using this command for each interface.
network address wildcard-mask area area-id
Where wildcard ...
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1
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Can not create sub-interface like `interface gigabitEthernet 2/1.100`
I follow a tutorial, there shows the method of create sub-interface:
but in my actual situation, I can not do this:
Router(config)#interface gigabitEthernet 2/1.100
...
- 1,767
4
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2
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Why the Cisco Router's loopback interface can not be showed up by default?
By default, why the Cisco Router's loopback interface can not be showed up?
Router#show ip interface brief
Interface IP-Address OK? Method Status Protocol
...
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6
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3
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How not to route on a Cisco router
So we have a router, with a switch card interface, 8 ports
Say I have 4 VLANs (A,B,C,D) on it, with 2 switch ports in each.
Each VLAN (i.e. all ports) can communicate with each other, because ...
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My interface do not have a IP address in a segment, but I can ping the IPs of it
You see, in my local Mac's network interface there is no 172.18.1.*:
$ ifconfig
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
options=1203<RXCSUM,TXCSUM,TXSTATUS,SW_TIMESTAMP&...
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1
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297
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Network interface issues an ARP request to get the MAC address of an actively used gateway
My network interface actively uses a gateway to send IP packets to other networks. There is already an ARP entry in the cache for the IP/MAC association for the gateway.
Is it normal that my network ...
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3
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Interfaces named with `ge` represent what?
I see a information:
Most interfaces are named according to:
- Interface media type (ge, so, at, and so forth)
...
I know the so represent SONET, at represnet ATM, but how about the ge ? if it ...
- 535
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2
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182
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Identify IP of the client causing high interface usage on uplink port
Background:
We are observing a high interface load (spikes up to 1G) on a WAN (dedicated link) uplink port of a Cisco switch. How can we find the IP of the client that is causing this high load?
I ...
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3
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Empty mac address value [closed]
Is there some MAC address value, that can be used to denote that device does not have MAC set (something like 0.0.0.0 for IP).? I thought of ff:ff:ff:ff:ff:ff, but afraid that it could be meaningful ...
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2
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Network Gateways vs Interfaces
When looking at the contents of a routing table section on the Wikipedia article on Routing Tables, it contains a table as an example of a routing table with two headings which have an unclear ...
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2
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218
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Why it is neccesary to assign IP adresses to interfaces?
I know this is a very very basic doubt, but never I thought of it in a deep perspective. For example, I am going to use the following scenario:
You know that we usually use a /30 mask when you are ...
- 143
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votes
1
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584
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Trunk on the outside ASA interface
I have a topology as in the picture. It is designed to be a factory network. 2 ASAs in a failover cluster border the whole LAN. And it is pretty much clear how to configure them: outside interface to ...
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Is TCP checksum verification also offloaded to NICs? [closed]
I understand that checksum calculation at the sender side is often offloaded to the NIC. Does this also happen for verification at the receiving end?
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Subnetting and switch configuration (CISCO Packet tracer)
I'd like to ask couple questions that I have about subnetting and switch configuration (more about latter).
Currently, I have subnetted my network to be on IP 192.168.10.0/29 with subnet mask 255.255....
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1
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GNS3 wic vs slot
can any one explain the difference between WIC vs Slot?
plus I want to have more L3 links in GNS3 but I cannot have more than 4 on 3725 router. there are two built in plus i can add two NM-1FE-TX in ...
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1
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209
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EHWIC-1GE-SFP for Cisco 1941
I was able to configure the interface but only the GE port is working, not the SFP port.
Did I miss something?
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2
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2k
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Ping loopback without interface IP address
I have two routers attached directly and both of them has loopback address. The interface has no IP address, I have just connected R1 g0/0 to R5 g0/0. If I put IP address on the g0/0 interface of both ...
- 123
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1
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3k
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"Gateway of last resort is not set" even though I have a default route to a tunnel interface
I work with Cisco CSRs. On all of my previous CSRs in AWS, I have the following:
AWS-ENV-CSR-R1#sh run | in ip route
ip route 0.0.0.0 0.0.0.0 Tunnel1
ip route 0.0.0.0 0.0.0.0 Tunnel2 2
AWS-ENV-CSR-...
1
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2
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494
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Physical / Virtual Interfaces.
Well, I know that's a simple question for the level of this forum, but yet, I didn't found anything on Google, at least not what I want.
I'm studying for CCNA R&S and I just learned about ...
- 15
2
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1
answer
342
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Can I curl a Cisco sg300 switch to get running config, MAC address table, int des, etc.?
I'm auditing switch interface descriptions at work. I work nights and sometimes people during the day shut down their computers when they leave, so I don't see which computers are on interfaces when I'...
- 416
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2
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120
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What are parts of interface name called
Consider this interface name GigabitEthernet1/0/48
I know that GigabitEthernet is an interface type. What does 1, 0 and 48 stand for?
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2
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Aruba OS equivalent for default interface
I need to reset or default an interface on an Aruba switch. This may be the same for HP procurve switches, but I am not sure. On Cisco, the command would be default interface in global config mode. Is ...
- 325
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3
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772
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Inter-vlan routing with unmanaged switch?
I have a Cisco 3650 with inter-vlan routing enabled. All vlans reach each other with no problems. The problem appeared when I connected an unmanaged switch to an interface on the cisco. I set up a ...
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