Questions tagged [interface]

For questions about a physical or virtual interface on a network device. For instance: Interface configurations, troubleshooting and security.

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Brocade XMR randomly losing virtual interface IP address

We have a pair of XMR routers configured 100+ VLANs running VSRP downstream and BGP upstream. At random times, the IP information is deleted and I have to go in and reset it. Each VLAN config looks ...
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1answer
30 views

Static IP assignment 3750X - DHCP Override

I have a 3750X that I am running some testing with. I have a VLAN interface that is using 10.10.10.254/21 as it's primary IP and 192.168.10.254/24 as it's secondary IP. See below: interface Vlan10 ...
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1answer
108 views

Switching interface VLAN ID Mid-Production

I was wondering if there was a way to switch out the VLAN ID from VLAN1 to VLAN10 without impacting the connectivity of the end users? Can I simply copy and paste from one interface VLAN to another? ...
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1answer
89 views

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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1answer
3k views

Configure ethernet ports on a router in packet tracer 7

I have some issue to configure the router in Packet Tracer 7. I have a router with a specific subnet, which is 192.168.1.128/27 . My first problem is, how can I configure two (or more) ethernet ...
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2answers
101 views

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 ...
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3answers
74 views

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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1answer
49 views

Can not add a Physical port into LAG

Using SuperMicro network module, which related to Intel SDN product, the command PDF . and the Web GUI manual. there I have qe57, qe61, qe65, qe69 four upstream ports, I want to aggregate them to one ...
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6answers
4k views

Why do I need to specify a subnet mask on interface?

When assigning an IP address to an interface, why do I need to specify a subnet mask? I understand the purpose of subnet masks in a routing table for example (to specify a range of IP addresses as ...
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0answers
21 views

routing with multiple NICs (connected to multiple APs) that were all assigned the same LAN address [closed]

I have 4 wireless APs based on the ESP8266. These APs all broadcast distinct SSIDs, but each serves LAN addresses in subnet 192.168.4.XXX. The subnet value is not configurable. Then, I have a Linux ...
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2answers
49 views

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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1answer
40 views

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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1answer
228 views

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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2answers
60 views

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, ...
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2answers
231 views

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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30 views

Why does my 1921 Router not bring up its interfaces?

I have the 'no shut' command entered on both interfaces. They work when I enter the command. I copy run start 'wr' Power was cycled for the Router, Switch (3560x-24), Cable modem and AP. They were ...
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1answer
52 views

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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2answers
309 views

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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1answer
47 views

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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1answer
24 views

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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2answers
56 views

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; ...
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4answers
5k views

DLink switch loses configuration on power off!

We just bought a DGS-1210-28P smart switch, it is my first experience with a business class switch, however I found a pretty weird behavior. The switch loses all of its configurations, even management ...
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2answers
156 views

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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2answers
93 views

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 ...
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1answer
49 views

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)?
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1answer
44 views

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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3answers
583 views

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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5answers
10k views

How many IP addresses can a device or an interface possess?

Can one IP address be assigned to more then one device or interface? In which situations may this happen? Can one device or interface posses more than one IP address?
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1answer
145 views

Clustered Juniper devices using public DoD IP addresses for communication?

Ok, so I have to admit I am not an expert in how Juniper networked devices work, so this entire issue might be why I am having issues understanding something I am seeing on a pair of clustered SRX210H'...
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2answers
127 views

What does it mean if an Ethernet Card has two RJ45 ports?

Ethernet is below IP in the OSI model. But how is an IP address actually assigned to an Ethernet port? I know, that Ethernet has nothing to do with IP, but under Windows I can assign an IP address ...
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2answers
963 views

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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2answers
332 views

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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1answer
294 views

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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2answers
1k views

Cisco 3560 interface counters, are the counters reset automatically?

I have a Cisco 3560G switch. Are the interface counters reset automatically, recalculated in a specific interval (5 minutes?), or not at all? I want to get (hourly, daily, monthly, etc) interface ...
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1answer
2k views

Why is my ACL not blocking traffic on my cisco router interface?

So here is my config. I want traffic coming from all networks except 172.23.1.0/24 to be blocked by inferface fa 0/0 So on the router I creater 2 ACLs ACL 10 R1# access-list 10 permit 172.23.1.0 0....
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1answer
403 views

What is the max throughput I should expect a Cisco 3560-PoE to have for a small network?

I have a Cisco 3560 48-PoE. I am trying to use it for imaging computers. I can make it work but I only get 1gb a minute. I have tried various tweaking but that's about has high as I can get. What ...
4
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1answer
872 views

limit bandwidth on a Cisco switch port,

Our company has a 3/.5 DSL connection. On this connection we have a VPN where the execs are able to access files on the network as well as VOIP. On this connection we also have our exchange email ...
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1answer
410 views

How “show inventory” displays SX SFP?

I've a Cisco 3925 and it's not quite clear why an "1000BASE-SX SFP" entry is visible in the inventory. Is it only visible when the SX SFP is in use? (I've no chance to modify it.) NAME: "CISCO3925-...
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2answers
568 views

Command for showing unused ports over time on Cisco switches

I was looking at a previous question about this where a command was given to look for all ports that had not been used in 6 weeks. I ran the command but it doesn't give the port names just the line ...
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1answer
37 views

How do i set this ACL on the router

I was told in a previous answer to use ip access-list extended TEST deny ip host <PC0 address> host <PC5 address> permit ip any any But, whats the command to set it on the router ...
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1answer
258 views

how to connect 2 routers to communicate?

What cable connects routers to communicate ? I am using Packet Tracer Simulator, and I connected 2 routers using a DTE connector. After doing this, I am unable to ping between the 2 routers. Is using ...
2
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2answers
6k views

what are input errors on the CISCO switch?

In my topology, I have connected spirent - traffic generator to MRV switch ( L1 switch) and then connected to CISCO switch. I am seeing some input errors on this interface. What does it mean? Does it ...
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2answers
167 views

Required VLAN overlapping allowed?

I configured the switch for two VLANs, as below: Projects-3560-(config)#int vlan11 Projects-3560-(config-if)#ip address 10.110.1.1 255.255.255.0 Projects-3560-(config)#int vlan10 Projects-3560-(...
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1answer
17k views

How to know the interface utilization on a Cisco switch?

I would like to confirm. Is the above below information in bold sufficient to know the utilization of my interface in percentage? Switch#sho int fa0/8 FastEthernet0/8 is up, line protocol is up (...
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3answers
108 views

Gigabit NIC stuck on 100mbs

My main problem started when i installed 4 gigabit NIC into my computer. The 4 NIC are connected to GB linksys switches, each in different location,1 of the 4 gives GB and the others are stuck on 100 ...
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1answer
1k views

How exactly is “input rate” calculated in IOS “sh int” output?

Cisco IOS routers display input and output bps and pps values for load-interval time period in sh int output. For example here is load-interval set to 30 seconds: C1921#sh int Gi0/1 | i rate 30 ...
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1answer
63 views

Why switch (2950) port configuration is needed when NIC adapter is configuired?

I have two Cisco 2950 switches connected with a Dell 7810 machine to provide network redundancy. The machine is equipped with one built in (On Mother Board) Ethernet port and with a dual port NIC “...
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5answers
1k views

IPv6 address assigned to vlan interface of 3750 switch changes

When setting up my 3750 stacks, I enable IPv6 on the Vlan1 interface so that I can manage the stack over IPv6. The stacks are not doing any layer 3 routing. However, it seems that the IPv6 address ...
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1answer
33 views

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 ...
3
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1answer
541 views

Does traceroute show the IP address of the entry port? or exit port?

Does traceroute show the IP address of the entry port? or exit port? For example, if there is an intermediary router in the path with 198.28.56.18 facing the source (entry port), and 65.86.24.136 ...