Networking

  • Comments About Networking Technology


    We've noticed in many ways that traditional networking even in WANs and LANs has changed very little. Years ago most networks were running on 100mbit and today most still are. Even the average internet connection is largely unchanged from several years ago with some minor exceptions from Europe and Asia.
  • HP Procurve Switch 2824 CLI Telnet Experience , Guide and Tutorial


    telnet 192.168.1.54 ------------------------------------- ProCurve J4903A Switch 2824 Software revision I.10.77 Copyright (C) 1991-2009 Hewlett-Packard Co. All Rights Reserved. RESTRICTED RIGHTS LEGEND Use, duplication, or disclosure by the Government is subject to restrictions as set forth in subdivision (b) (3) (ii) of the Rights in Technical Data and Computer Software clause at 52.227-7013. HEWLETT-PACKARD COMPANY, 3000 Hanover St., Palo Alto, CA 94303 We'd like to keep you up to date about: * Software feature updates * New product announcements * Special events Please register your products now at: www.ProCurve.com Press any key to continue ------------------------------------------- LACP Problems - Be Warned - Disable LACP Unless You Need It! Disable LACP, this is the link aggregation protocol where you can combine 4 ports to increase the overall bandwidth. This sure sounds great but all LACP ports should be disabled unless you are using it. The reason is because it often takes down ports of computers/servers for no apparent or justified reason and it is a pain to troubleshoot. LACP should only be enabled on ports that are actually going to use LACP. Symptoms in the log are as follows: I 01/02/90 01:41:36 ports: port 7 is Blocked by LACP I 01/02/90 01:41:39 ports: port 7 is now on-line I 01/02/90 01:45:23 ports: port 7 is now off-line I 01/02/90 01:45:48 ports: port 7 is Blocked by LACP I 01/02/90 01:45:51 ports: port 7 is now on-line I 01/02/90 01:56:47 ports: port 7 is now off-line I 01/02/90 02:22:42 ports: port 7 is Blocked by LACP I 01/02/90 02:22:42 ports: port 7 is now off-line I 01/02/90 02:39:44 ports: port 7 is Blocked by LACP I 01/02/90 02:39:47 ports: port 7 is now on-line I 01/02/90 02:45:15 ports: port 7 is now off-line I 01/02/90 02:56:42 ports: port 7 is Blocked by LACP I 01/02/90 02:56:45 ports: port 7 is now on-line I 01/02/90 02:57:44 ports: port 7 is now off-line #check if you have lacp enabled on any ports show lacp no LACP ports found. How to disable LACP: *Warning if you have machines that do not come back automatically if the link goes up and down be warned that this could take some or all machines offline and needs physical intervention. When I typed the "no interface all lacp" this took down most computers on the switch and they did not come back on their own except a few. ProCurve Switch 2824# config ProCurve Switch 2824(config)# ProCurve Switch 2824(config)# no interface all lacp wr mem Disable port *Warning about port disable/enable is that I find some servers detect the uplink but will not work after being re-enabled without a network restart (eg. service network restart The "8" represents port numbers. You can also do a range such as "8-15" config int ethernet 8 disable --------------------------- Enable Port *Warning about port disable/enable is that I find some servers detect the uplink but will not work after being re-enabled without a network restart (eg. service network restart config int ethernet 8 enable ------------------------------------ Check each port's bandwidth usage in mbit The "Util" field is how many mbit per second the port is doing. You need to base the % percentage off the port speed eg. 10,100 or 1000 mbit. Port Mode | --------------------------- | --------------------------- | Kbits/sec Pkts/sec Util | Kbits/sec Pkts/sec Util --------- -------- + ---------- ---------- ----- + ---------- ---------- ----- 1 1000FDx | 5016 15 00.50 | 5040 47 00.50 2 1000FDx | 0 0 0 | 0 0 0 3 1000FDx | 2536 0 00.25 | 5024 32 00.50 4 1000FDx | 12376 691 01.23 | 5352 448 00.53 5 1000FDx | 600 0 00.06 | 5024 32 00.50 6 1000FDx | 3960 0 00.39 | 5024 32 00.50 7 1000FDx | 5360 77 00.53 | 5344 112 00.53 8 1000FDx | 0 0 0 | 0 0 0 9 1000FDx | 2488 0 00.24 | 5024 32 00.50 10 1000FDx | 2536 0 00.25 | 5024 32 00.50 11 1000FDx | 2488 0 00.24 | 5024 32 00.50 12 1000FDx | 2472 0 00.24 | 5024 32 00.50 13 1000FDx | 0 0 0 | 0 0 0 14 1000FDx | 0 0 0 | 0 0 0 15 1000FDx | 0 0 0 | 0 0 0 16 1000FDx | 0 0 0 | 0 0 0 17 1000FDx | 0 0 0 | 0 0 0 18 1000FDx | 0 0 0 | 0 0 0 19 1000FDx | 5680 538 00.56 | 12760 784 01.27 20 100HDx | 0 0 0 | 520 32 00.52 21 1000FDx | 0 0 0 | 0 0 0 22 1000FDx | 0 0 0 | 0 0 0 23 1000FDx | 0 0 0 | 0 0 0 24 1000FDx | 0 0 0 | 0 0 0 ------------------------------------------------------------- Show What Port MAC Address Belongs To show mac 00:1F:D0:00:13:CC Status and Counters - Address Table - 001fd0-0013cc MAC Address : 001fd0-0013cc Located on Port : 8 Show All MAC Addresses By Port show mac all If no MAC is displayed it means no device is connected or the device is not active or the port on the switch may be bad or disabled. Status and Counters - Port Address Table - 17 MAC Address ------------- show specific port mac show mac 10 Check overall port status show interfaces is very useful for counting traffic and also identifying network issues Status and Counters - Port Status | Intrusion MDI Flow Bcast Port Type | Alert Enabled Status Mode Mode Ctrl Limit ----- --------- + --------- ------- ------ ---------- ----- ----- ------ 1 100/1000T | No Yes Up 1000FDx MDIX off 0 2 100/1000T | No Yes Down 1000FDx MDIX off 0 3 100/1000T | No Yes Up 1000FDx MDI off 0 4 100/1000T | No Yes Up 1000FDx MDIX off 0 5 100/1000T | No Yes Up 1000FDx MDIX off 0 6 100/1000T | No Yes Up 1000FDx MDI off 0 7 100/1000T | No Yes Up 1000FDx MDI off 0 8 100/1000T | No No Down 1000FDx MDI off 0 9 100/1000T | No Yes Up 1000FDx MDI off 0 10 100/1000T | No Yes Up 1000FDx MDI off 0 11 100/1000T | No Yes Up 1000FDx MDI off 0 12 100/1000T | No Yes Up 1000FDx MDI off 0 13 100/1000T | No Yes Down 1000FDx MDI off 0 14 100/1000T | No Yes Down 1000FDx MDI off 0 15 100/1000T | No Yes Down 1000FDx MDIX off 0 16 100/1000T | No Yes Down 1000FDx MDIX off 0 17 100/1000T | No Yes Down 1000FDx MDIX off 0 18 100/1000T | No Yes Down 1000FDx MDIX off 0 19 100/1000T | No Yes Up 1000FDx MDIX off 0 20 100/1000T | No Yes Up 100HDx MDIX off 0 21 100/1000T | No Yes Down 1000FDx MDIX off 0 22 100/1000T | No Yes Down 1000FDx MDI off 0 23 100/1000T | No Yes Down 1000FDx MDI off 0 24 100/1000T | No Yes Down 1000FDx MDIX off 0 show interfaces gives you more detail Notice Port 7 showing 203 "Errors Rx". It was because of a bad cable and we wondered why that server had spotty connectivity. Status and Counters - Port Counters Flow Bcast Port Total Bytes Total Frames Errors Rx Drops Rx Ctrl Limit ----- ------------ ------------ ------------ ------------ ----- ------ 1 3,164,403... 2,285,255... 0 0 off 0 2 457,687,164 2,150,118... 0 0 off 0 3 3,716,409... 2,795,214... 14 0 off 0 4 1,897,977... 2,207,705... 0 0 off 0 5 626,012,466 3,843,597... 0 0 off 0 6 2,628,057... 2,138,559... 0 0 off 0 7 1,498,582... 476,790,025 0 0 off 0 8 2,830,274... 1,696,622... 589 0 off 0 9 1,573,201... 3,990,337... 0 0 off 0 10 1,930,438... 2,808,292... 238 0 off 0 11 3,137,823... 3,577,438... 1476 0 off 0 12 2,363,525... 99,291,760 1102 0 off 0 13 0 0 0 0 off 0 14 0 0 0 0 off 0 15 0 0 0 0 off 0 16 0 0 0 0 off 0 17 0 0 0 0 off 0 18 0 0 0 0 off 0 19 2,186,889... 2,963,434... 1 0 off 0 20 530,240,341 746,865,357 581 0 off 0 21 1866 7 2 0 off 0 22 2288 7 2 0 off 0 23 2246 7 2 0 off 0 24 190,610 1821 2 0 off 0 Password Issues/Requirements Note that these switches support a maximum of 16 characters. Spaces cannot be used and it is not obvious if you have gone over the limit so if you cannot login after setting a password type it out and count 16 characters and use only those and you should be able to login. If your password is lost/unknown you can reset just the password (not the switch settings) by holding the "Clear" button on the front of the switch for at least 1 second. Note again this does not reset the switch config but only the password when done this way.
  • Windows Server 2012, 2016, 2019 How To Install and Missing Disabled Telnet Client


    By default telnet is not enabled or installed on the latest Windows servers so you'll get an error saying: telnet is not recognized as an internal or external command dism /online /Enable-Feature /FeatureName:TelnetClient
  • Cisco Switch Setup Guide Command List


    Enter configuration console: enable configure terminal This is important because if your console doesn't look like below none of the commands will work! Switch(config)# Save and Apply Settings wr Show Switch Configuration: show run Show Port List/Status: Switch#show interface status Port Name Status Vlan Duplex Speed Type Fa0/1 connected 1 a-full a-100 10/100BaseTX Fa0/2 notconnect 1 auto auto 10/100BaseTX Fa0/3 notconnect 1 auto auto 10/100BaseTX Fa0/4 notconnect 1 auto auto 10/100BaseTX Fa0/5 notconnect 1 auto auto 10/100BaseTX Fa0/6 notconnect 1 auto auto 10/100BaseTX Fa0/7 notconnect 1 auto auto 10/100BaseTX Fa0/8 notconnect 1 auto auto 10/100BaseTX Fa0/9 notconnect 1 auto auto 10/100BaseTX Fa0/10 notconnect 1 auto auto 10/100BaseTX Fa0/11 notconnect 1 auto auto 10/100BaseTX Fa0/12 notconnect 1 auto auto 10/100BaseTX Fa0/13 notconnect 1 auto auto 10/100BaseTX Fa0/14 notconnect 1 auto auto 10/100BaseTX Fa0/15 notconnect 1 auto auto 10/100BaseTX Fa0/16 notconnect 1 auto auto 10/100BaseTX Fa0/17 notconnect 1 auto auto 10/100BaseTX Fa0/18 notconnect 1 auto auto 10/100BaseTX Fa0/19 notconnect 1 auto auto 10/100BaseTX Fa0/20 notconnect 1 auto auto 10/100BaseTX Fa0/21 notconnect 1 auto auto 10/100BaseTX Fa0/22 notconnect 1 auto auto 10/100BaseTX Fa0/23 notconnect 1 auto auto 10/100BaseTX Fa0/24 notconnect 1 auto auto 10/100BaseTX Gi0/1 connected 1 a-full a-1000 10/100/1000BaseTX Gi0/2 notconnect 1 auto auto Not Present Show config of individual port or vlan You could also have used "interface vlan 1" and you would get the config of the vlan. Switch#show running-config interface gi0/1 Building configuration... Current configuration : 36 bytes ! interface GigabitEthernet0/1 end Show all VLANs: show vlan VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4 Fa0/5, Fa0/6, Fa0/7, Fa0/8 Fa0/9, Fa0/10, Fa0/11, Fa0/12 Fa0/13, Fa0/14, Fa0/15, Fa0/16 Fa0/17, Fa0/18, Fa0/19, Fa0/20 Fa0/21, Fa0/22, Fa0/23, Fa0/24 Gi0/1, Gi0/2 1002 fddi-default act/unsup 1003 token-ring-default act/unsup 1004 fddinet-default act/unsup 1005 trnet-default act/unsup VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2 ---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------ 1 enet 100001 1500 - - - - - 0 0 1002 fddi 101002 1500 - - - - - 0 0 1003 tr 101003 1500 - - - - - 0 0 1004 fdnet 101004 1500 - - - ieee - 0 0 1005 trnet 101005 1500 - - - ibm - 0 0 Show Specific VLAN show vlan id 1 Configure interfaces 100M Ethernet is normally known as fa0 So for port 1 you would use fa0/1 int fa0/1 or int fastethernet0/1 1Gig Ethernet known as gigabitethernet or gi0 int gigabitethernet0/1 or int gi0/1 You can configure vlans in the same way: int vlan 1 Working with a range of ports (example of ports 1-12) int range fa0/1-12 Enable Port(s) int fa0/1 no shutdown The no in front of shutdown means turn on the port (the opposite or !) How to Assign ports to vlan #how to assign ports to vlan in this case it is ports 1-24 and they are being assigned to vlan 1 Switch(config)#int range fa0/1-24 Switch(config-if-range)#switchport access vlan 1 Port Security Maximum MAC addresses/devices Where 8 below is the maximum number of MAC's rtt(config)#int fa0/3 rtt(config-if)#switchport port-security maximum 8 To Disable MAC Limit rtt(config-if)#no switchport port-security maximum How To Disable Port Security On A Port no switchport port-security no switchport port-security violation protect no switchport port-security mac-address sticky no switchport mode access BPDU Guard This can be the source of a lot of pain for end users and network admins. To understand this, first let's talk about STP (Spanning Tree Protocol) which is designed to prevent routing loops that would otherwise kill a network. A routing loop could be something as simple as an ethernet cable that has both ends plugged into the same switch. STPworks by exchanging BPDU (Bridge Protocol Data Units) which are multicast messages sent out and contain info like the source MAC, switch ID, originating switch port, switch port priority. It then uses an algorithm based on the BPDU information to create an STA (Spanning Tree Algorithm) at the layer 2 level and will shut down a port if it is creating a loop. Now BPDU Guard in the world of Cisco just means that if it receives a BPDU it will shutdown the port in errdisable. I say this is good in terms of keeping a network secure and running well, but a pain for end users who need to run a managed switch and for network admins who were unaware that BPDU was enabled. Check a port's settings and you may see this: rtt#show run int gi0/1 Building configuration... Current configuration : 335 bytes ! interface GigabitEthernet0/1 switchport access vlan 999 switchport mode access switchport port-security switchport port-security aging time 2 switchport port-security violation restrict switchport port-security aging type inactivity macro description cisco-desktop spanning-tree portfast spanning-tree bpduguard enable end To disable bpduguard rtt(config-if)#spanning-tree bpduguard disable To enable bpduguard rtt(config-if)#spanning-tree bpduguard enable *Note you can also enable or disable BPDUguard globally by just being in conf t #enable by default rtt(config)#spanning-tree portfast bpduguard default #disable by default rtt(config)#no spanning-tree portfast bpduguard default How to assign IP to VLAN Choose your interface eg vlan 777 Where below 10.25.20.2 is the IP and the netmask is 255.255.255.0 Switch(config-if)#ip address 10.25.20.2 255.255.255.0 Assign the default gateway: Switch(config-if)#ip default-gateway 10.25.20.1 How To Set Administrative "enable" mode Password Switch(config)#enable password realtechtalk.com DHCP Server Creation for VLAN Create VLAN and assign IP 10.25.2.2 and DFGW 10.25.2.1 switch(config-if)#int vlan 1800 switch(config-if)#ip address 10.25.2.2 255.255.255.0 switch(config-if)#ip default-gateway 10.25.2.1 #you could add Option 150 if this VLANis for phones and you have a CUCM Server (specify the CUCM server IP) switch(dhcp-config)#option 150 ip 10.25.2.8 Create DHCP Pool for VLAN 1800 range 10.25.2.0 switch(config)#ip dhcp pool Update switch(dhcp-config)#network 10.25.2.0 255.255.255.0 switch(dhcp-config)#dns-server 8.8.8.8 4.2.2.1 switch(dhcp-config)#default-router 10.25.2.1 Exclude Relevant Addresses switch(config)#ip dhcp excluded-address 10.25.2.1 10.25.2.2 Troubleshooting Why can't I ping or connect to my VLAN IP? Make sure the VLAN that has the IP is assigned to a port Make sure the IP address is correct and it has the appropriate default gateway if necessary Make sure your client side machine has an IP on that subnet AND that you have a route to it through the right adapter (eg. in Linux ip route add 10.10.25.0/24 dev eth0)*Remember to specify the /24 or whatever mask you desire and the right device. Is the port and VLAN in a noshut state?
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