Mario Jost
  • Member for 2 years, 10 months
  • Last seen more than a month ago
Why does DHCP use UDP and not TCP?
76 votes

DHCP cannot use TCP as the transport protocol because TCP requires both end-points to have unique IP addresses. At the time a host is required to use DHCP, it does not have an IP address it can source ...

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On a 3560E Switch
7 votes

Most likely there is no Vlan interface on your switch. You can see, I have vlan10 and vlan11: swTST01#show vlan | include VLAN VLAN Name Status Ports 10 LAN_VLAN ...

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Cellular interface in VRF (LTE)
Accepted answer
4 votes

Just got it to work. The trick is to have something that generates traffic and triggers the cellular interface to connect. Didnt relize that the IP SLA i had configured on the global vrf made the ...

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Routing question on a Cisco router
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4 votes

Yes, directly connected interface have a higher priority than a static route. Have a look at this table: You can use the command show ip route and you will see, that the static route is not in the ...

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What can I use to block all the ports of the WAN in a Cisco router?
Accepted answer
3 votes

So i recommend using IP inspect. This is a fairly new'ish configuration (compared to reclexive ACLs) and is very lightweight compared to ZBF. So you create a ACL where you want to allow everything ...

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SNMPv3 context on IOS-XE does not seem to work with Prime
Accepted answer
2 votes

I found a fix for this. The trick is not to put the read community in the command. So we deployed this to all the IOS and IOS-XE switches and it works for all Vlans: snmp-server group COMPANY v3 priv ...

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How is the MD5 hash calculated in BGP?
2 votes

I am guessing you are talking about authentication. To calculate the MD5 checksum, BGP needs to take some information as a base to calculate. If it would only use the password, it would be easy to ...

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Connect routers in gns3
2 votes

R1 and R2 are not in the same subnet. R1 is in 131.43.43.1/27 and R2 is in 131.44.44.2/27. Put R2 into 131.43.43.2/27 and it should work. You already wrote, that the IP ranges do not overlap. So, ...

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C3PL working order
Accepted answer
2 votes

There are 2 different matching variations for class maps. Either match-any or match-all: match-all = logical AND of all conditions all conditions must be true for a match match-any = logical OR of ...

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LAN connection with out VPN
2 votes

Yes, most ISP's provide Layer3 connections between different branch locations. The provider then, dont have to use a VPN, cause they own the network in between your locations. For you, this is a ...

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Cisco IOS - Delay DHCP offers
Accepted answer
1 votes

Just found a workaround. You can link the status of the DHCP server to a HSRP name: interface GigabitEthernet1 ip address 172.16.220.3 255.255.255.0 standby 10 ip 172.16.220.1 standby 10 priority ...

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Cisco IOS How to dynamically change the queueing/shaping upload bandwidth for xDSL circuits?
Accepted answer
1 votes

We have alot of Cisco 800 Series routers and the same issue. I create a TCL script that i scheduled on the router to run, so it would read out the xDSL synched upload bandwidth and configure the ...

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Traffic flow of tunnel interfaces
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1 votes

So i did some labbing and got to the results myself. This is a schematic of a Cisco 892FSP router. It has a built in switch, so we have to work with vlan interfaces. If we assume traffic flowing from ...

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How can I use an HTTP CRL on Cisco IOS?
1 votes

Not sure if I can help you with the command directly, but i can show you another way of checking CRLs within a trustpoint. See following configuration: Router(config)#crypto pki trustpoint INTERNALCA ...

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Is there a way to prioritize/manage WIFI traffic (in the WIFI realm)?
1 votes

There is a QoS implementation in WiFi networks called WMM. You can classify your traffic into 4 different categories. In bigger wireless environments like with the Cisco Wireless Lan Controller (WLC) ...

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How to exclude interfaces without description on 'sh int description' command using regex?
1 votes

If you wanna do it without the shell processing (which is not accessible by TCL for example) you can do it with following command: show interfaces description | include down[ ]+down[ ]+[A-Za-z0-9]|up[...

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Traceroute command last hop cannot be reached
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1 votes

Traceroute can be used to spy out a network. There are usually 2 ways, companies deal with blocking it. Fist: Devices will be configured to not reply to TTL=0 packets. But they will still allow other ...

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Suppress CLI terminal output on IOS
Accepted answer
1 votes

I managed to do what i wanted with a TCL script, that is sitting on the local flash storage. If i give a command, it will try to download a TCL script with the same name from the TFTP Server and does ...

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Trust dscp command missing on cisco 3850
Accepted answer
1 votes

Putting a "configurational" answer to my own question in case someone else stumbles upon the same question in the future... The following configuration on 2960X switches: class-map match-any ...

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