I am running DHCP snooping for VLAN 1 on below switch
IOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(22)EA4a, RELEASE SOFTWARE (fc1)
Model number: WS-C2950-24
Looks like below IOS does not support snooping.
Model number: WS-C2950-24
IOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(14)EA1a, RELEASE SOFTWARE (fc1)
What image i would need for my 2950 to enable DHCP snooping and DAI features (just for lab purpose)?
or are these features just available on the bigger modular switches (4500 and 6500)?
>sh ver
Cisco Internetwork Operating System Software
IOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(22)EA8a, RELEASE SOFTWARE (fc1)
[Code].....
does Cisco 2600 series switch support 802.1x and DHCP snooping?
View 6 Replies View RelatedI using IOS c2950-i6k2l2q4-mz.121-22.EA14.bin but no support command "ip http secure-server" and I not connect switch by CNA. How I fix ? Or IOS C2950 support ip http secure-server and ssh ver2 ?
View 1 Replies View RelatedI am trying to configure interface vlan1 to get an ip address from dhcp by entering the commnad ip address dhcp ios rejects the dhcp portion of my command as not recognised although it is referred to in Cisco manuals.my IOS version is c2950-i6k2l2q4-mz.121-22.EA14.bin.I get the same problem when I try to configure ip http secure-server on the switch. Is this a known bug or whether I have the correct IOS version for these commands?
View 6 Replies View Relatedan attacker have configured his PC with an static IP address but there is no such entry configured statically in switch, neither in DHCP snooping database.now when he want to generate traffic will switch block him? because there is no entry of his PC in the switch database.
View 2 Replies View RelatedI have an issue with SRW2024P-K9-BR (SG300). Datasheet and configuration guide show me that is possible configure DHCP snooping in this switches, but web interface and console don't appear related menus/commands.
I'm using firmware version 1.1.2.0 and didn't found anything about this here.
I have a problem at a place where 5 ME3400 switches are connected in a straight line. I can't do much about the topology of that place, but the problem is they are all DHCP Snooping, but uni cast replies from the dhcp server further up the hierarchy gets eaten by the first switch! I can't really see why it not only inspects in and whines about it not being for itself - it then drops the message.
What have we done wrong (apart from the actual layout of that place, which I can't really change)?
Sep 28 13:49:29: DHCP_SNOOPING: received new DHCP packet from input interface (GigabitEthernet0/1)
Sep 28 13:49:29: DHCP_SNOOPING: process new DHCP packet, message type: DHCPOFFER, input interface: Gi0/1, MAC da: 7444.012d.debd, MAC sa: 0013.1a4a.65c7, IP da: XX.YY.186.7, IP sa: XX.YY.186.1, DHCP ciaddr: 0.0.0.0, DHCP yiaddr: XX.YY.186.7, DHCP siaddr: 0.0.0.0, DHCP giaddr: 0.0.0.0, DHCP chaddr: 7444.012d.debd
Sep 28 13:49:29: DHCP_SNOOPING: binary dump of option 82, length: 20 data:
[Code] ......
It really should just send it on, as with any uni cast not on the switch itself - it should go out Gi0/2 really. Why isn't it?
[core] -- [sw1] -- [sw2] -- [sw3] -- [sw4] -- [sw5]
All the trunks are trusted, DAI is on (I've tried shutting it off, as well), port-security is used but it's actually not dying on the switch having the client computer, but the first one in the chain with dhcp snooping.
I have a problem with high CPU load by DHCP Snooping process on Catalyst 6506 (WS-SUP720-3B, soft: s72033-ipservices_wan-mz.122-18.SXF11.bin). I have it enabled on 15 VLANS, in which there are subscriber devices residing, and sending DHCP requests through Cisco to DHCP server (Cisco acts as DHCP relay, and it's collecting the snooping database, I also use DAI).
Snooping database contains 6962 bindings now.
CPU load goes high only sometimes, and I don't have a clue, why it's going so high. It can load as high as 45-47% of CPU, like this:
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
116 81471244 322596368 252 42.95% 43.48% 36.06% 0 DHCP Snooping
When the load is high, the command: show ip dhcp snooping statistics is showing, that the overall quantity of
Packets Processed by DHCP Snooping is increasing rapidly. In normal situations, it's like 10-20 packets per second, but when the load is high, it's 1000-10000 pps.
But when I look at SPAN from my subscriber's VLANS, I don't really see any flood of DHCP requests, or something like that - everything looks as usual. Maybe, some of subscriber's devices are sending incorrect DHCP requests, that are causing packets to loop inside RP, or something like that? How can I detect that thing?
Also I thought, that if I enable the ip dhcp snooping trust mode on all of the Catalyst interfaces, the DHCP snooping will not process the subscribers DHCP packets, and I can, by exclusion of interfaces from one to one, detect, from which interface the problem is originating. But this seems to be incorrect, I turned the ip dhcsp snooping trust on all interfaces, and I still get spikes of CPU load by DHCP snooping process. Why it's still examining packets, even on trusted interfaces, is it ok?
And one more question - if I disable the ip dhcp snooping globally, will it clear all my existing bindings in snooping database?
I have attempted to implement DHCP snooping and have been having some strange issues. I have 5 3560s taht I use for my edge and when I attempt to implement on all five, the VLAN that houses my voice data appears to no longer be able to recieve DHCP lease renewals so after the 24 expiration all of my phones lose their configs. Once I roll back the changes the voice VLAN comes back. The other VLANs seem to function correctly as theya re able to renew their DHCP addresses.
The 3560s tie into each other using GIG Ports 1 & 2 and the top and bottom switches tie into our core switch, a 4507. The config that I use is below, failry simple and straightforward.
4 of the 5 switches feed our general office vlans for voice and data however the 5th switch is there for expansion and not in use. As such I have left the config changes in place on it and have tied myself and a colleague into it and have been operating fine for over a week now. So the config that I use seems sound in theory and should work on the other 4 switches with no issue.
I am working in a environment that is classed as collapssed Layer 3 environment. We have a core 6500 with routed links to 3560's which are access switches.
We have layer 3 vlans on the access switches, one for data one for voice.On the layer 3 vlans we have ip helper addresses that are used for DHCP. The DHCP servers are located on the 6500.
I recently had a incident where someone plugged a netgear router into a desk point because they thought they could use it for a switch. This router then started to dish out IP addresses to people in the morning for those who came in and docked their laptops. 99% of people weren't affected because they have desktop PC's are their leases hadn't expired.
Now we have bpduguard, bpdufilter to prevent people from plugging in switches that send out BPDU's. However this doesn't prevent the above senario where someone plugs a router or a 'dumb' switch that doesn't send BPDU's.Because of the above senario I started looking at DHCP Snooping, but I am unsure on a couple of things.
With the topology of our network I understand that I don't need to configure IP DHCP Snooping Trust on the L3 uplinks to our core switch. From what I understand I just need to enable IP DHCP Snooping globaly and then on the VLAN's on the access switch (because of the L3 topology VLAN's are local to the access switches). Only if I had L2 uplinks to the core would I need to configure IP DHCP Snooping Trust on the trunk links.
I am trying to understand the basics of DHCP snooping. I have a just a 3560 switch and a laptop ( to get a DHCP address) and my DSL router which has a DHCP server running. On the switch I have enabled "IP DHCP Snooping" and "IP DHCP Snooping VLAN 1" plugged the laptop and DSL router in and the laptop gets and IP address, should it?
I thought all ports were untrusted by default so the DHCP server should be blocked at offering IP addresses? If I wanted the DHCP server to be allowed to offer IP's I thought I should need to trust the port.
I have a new catalyst 2960,and i want to enable DHCP SNOOPING,but,it doesn't work,the server is stilling offert addresses IP and it's not connected in a trusted port,the schema is very simple:1 switch catalyst 2960 PST-S,1 server dhcp and 1 pc client,the PC and the server are in VLAN 10,DHCP SNOOPING is enabled in all ports and no port is trusted,but the client get addresse IP after retyping ipconfig /release and ipconfig /renew in dos commande.the configuration and the version of the switch are in the file attached.I tested the same configuration in a catalyst C3560-24PS and DHCP SNOOPING work normally,i tested in other catalyst 2960-PST-S,but the same probléme:DHCP SNOOPING without effect,the commands typed is:
-ip dhcp snnoping
-ip dhcp snooping vlan 10
I got some problem with enabling dhcp snooping on 4500 (cat4500e-lanbasek9-mz.122-54.SG.bin) the topology is as below: dhcp snooping enabled only on CORE (with interface trusted to dhcp server)the problem is that I put these 2 commands
ip dhcp snooping
ip dhcp snooping vlan 1
but it is not enabled on any vlan
SW-CORE#sh ip dhcp snooping
Switch DHCP snooping is enabled
DHCP snooping is configured on following VLANs:
none
DHCP snooping is operational on following VLANs:
[Code]...
On B1 if I turn it on there is a "1" in the section " DHCP snooping is configured on following VLANs:" but on core no.As you can see I did put the trusted on the interface in the direction to the dhcp.First I thought it can be a problem with option 82, I've read a lot about the issues with that, but the problem would be explicable if the client did receive IP address, but it does.
I am trying to find a command for dhcp snooping rate-limiting on a CatOS. The PFC card is PFC. PFC3B is said to support that command. But there seems no this command.
-6k> (enable) sh ver
WS-C6509-E Software, Version NmpSW: 8.4(5)
Copyright (c) 1995-2005 by Cisco Systems
NMP S/W compiled on Aug 3 2005, 13:26:46
[Code] ......
Up time is 1183 days, 1 hour, 41 minutes
I recently installed DHCP snooping on a 3750v2 switch (Version 12.2(55)SE4) and configured the uplink(Po2) as a trusted port. The problem is that clients cannot receive an IP address. When I disable DHCP snooping it is working properly. DHCP snooping is configured correctly but I don't have an idea how to resolve it. [code]I tested the solution on the same kind of hardware switch and firmware and it worked out fine. What is causing the clients not to receive an IP address from the DHCP server?
View 10 Replies View RelatedJust spoke to the TAC and didn't get the information needed. When configuring ip dhcp snooping database I am adding this to my configuration:ip dhcp snooping database scp://dhcpsec@192.168.1.50/home/dhcpsec/switch1.dhcp.database.txt..I assumed that to do this I would either specify the password on the command line, similar to the way its done when using ftp/http, or that I would need to create a public/private key.I have enabled scp and can manually copy a file from the switch to the linux server. So I believe I have all the aaa commands correct. Cisco WS-C3560G-24PS System image file is "flash:/c3560-ipservicesk9-mz.122-55.SE.bin".
View 3 Replies View Relatedi have a strange problem in my campus network.im trying to run port security on my access switches which they are 3550 with ios c3550-ipservicesk9-mz.122-52.SE when i run the port security with Sticky option, even i put 1000 mac address for just learning on the port but when i issue the switchport port-security command every pc connected to that port loses its connection with network UNTIL i enable dhcp snooping!!! all my client are getting they ip address from DHCP server but strange thing is that how on earth i have to enable DHCP snooping to port security work properly? also when i check the configuration under the interface when dhcp snooping is not yet enabled switch doesnt add any mac address under the interface so no one can work until i enable snooping and then switch adds mac addresses under the interface configuration.is this Bug on this version of IOS?[code]
View 4 Replies View Relatedwe've an infrastructure were the Access is based on Cat3750G Stacks connected to both Cores using L3 connections.On the Access Switches are implemented the following features DHCP Snooping, IP Source Guard and Dynamic ARP Inspection and all is working fine since years...the DHCP Servers are on a dedicated stack which act as a SFarm.
On the Access Switches the port configuration is the following:the Uplink Ports to both of the Cores are configured in TRUST for DHCP Snooping and ARP Inspection the Access Ports, where the end-device are connected, are UNTRUST for DHCP and ARP Inspection with IP Source Guard Active Right now I've to add a new L2 switch on one of the Access Port and I'm wondering if this is possible since I've to keep on the Stack Access Ports all the security feature active and I've also to implement DHCP Snooping on the new L2 switch to avoid rouge DHCP Server...
I suppose that the uplink to the L2 switch on the Stack Access Switch should be left as it is connected to an end device...but the uplink port on the L2 switch should be set up as TRUST...isn'it? Keeping in mind that I want to implement DHCP Snooping also on this L2 switch to avoid that Rogue DHCP Servers will impact the end-device connected to this L2 switch...is this scenario possible??? or I can't do that and should leave DHCP Snooping only on the Access Stack.
I have a problem with DHCP. I have two 2960 connected with a port channel on ports 47 and 48 as trunk with native vlan 10. I only have this one vlan. In port 1 of sw 1, I have a C800 as DHCP server.
I have an AP autonomous with single ssid on vlan 10. When I connect the AP to sw1, I receive dhcp with no problems.When I connect the AP to sw 2, I’m not getting IP by DHCP.I have DHCP snooping working on vlan 10 on both devices.
The ports where I connect the AP are access ports on vlan 10 config as trusted.The trunk ports are also configured as trusted.The port 1 of ws 1 that goes to the C800 is also configured as trusted.
figure out why I’m not getting IP by DHCP when I connect the AP to the SW 2.The only I notice is that when I connect the AP to sw 2, I get on SW 1 the message of packet drop by option 82, but even after configuring ip dhcp snooping information option allow-untrusted on both switches, the problem persists.
I've configured ip dhcp snooping on several vlans I want to monitor and the binding table doesn't seem to be building.eature DHCP is on, global ip dhcp snooping is enabled, VLAN snooping is enabled on the vlan's I want to monitor and my trusted interfaces are also configured. Alas no binding entries in the table! 7K is running 4.2(6).
View 1 Replies View RelatedWe have a DHCP SERVER implemented in a cisco router 2610.This router is connected to a switch cisco 2960 configured as DHCP SNOOPING. At the switch appear the next log message: [code] The ip address: 10.100.200.1 belongs to DHCP SERVER configured at router cisco 2610. What to do so these log messages does not appear any more? Do I need to do some configuration changes at some switch or router?
View 11 Replies View RelatedI need to apply DHCP snooping on 4500 series switches working as L2 in my Network. We have external DHCL Server in another location connected with 6500 series switch.
Running EIGRP Configured Voice & Data Vlan both
DHCP Server -------- 6509 switch<----------------------------------->6509 Switch -------- 4500 switch ----------------------------------------------------------Ip Phones.
(ving Redundant) (ving Redundant)
I need to know whether the configuration which I mentioned in scenario is enough for apply DHCP snooping in my network.
I have a C2950 Switch & I am trying to upgrade the IOS version of it so that I can proceed with learning about SSH. My current version of 12.1 does not have Enhanced Imaging. I am so new to Cisco, that I have spent hours trying to find the correct page, or link, or anything that can enable me to upgrade to a later version.
View 6 Replies View RelatedI have some issue from last 2 month on sf300.
The problem is that sf300 does not support complete dhcp, for that i put different internet modem.
I connected one internet modem in vlan 1 so users from that vlan can access internet and default gateway is nothing but Internet modem ip. user in the vlan are not communicate with other vlan because, other vlan users default gateway is Interface ip address. How i can give access to vlan 1 to access other vlan .
See the attached.
I have to used static route in all 3 devices or any one.
i' ve got 2 cisco 1130 AG AP's , i want both of them to broadcast 2 ssid's per AP, i've done so far but my clients cannot get a ip adress from the dhcp server.
View 19 Replies View RelatedI have an ASA5505 which provides internet (just internet) for about more than 600 pc/laptops. Can 5505's DHCP support this number?
View 4 Replies View RelatedI would like to know cisco 3560X-24P-S will support LLDP & DHCP relay .If it support which IOS feature is required to enbale these features.
View 1 Replies View RelatedCan I configure a DHCP Servero on the Nexus 7018?
View 2 Replies View RelatedI am playing around with a WS-C2950-24 running IOS 12.1(22)EA13. I would like to separate guest clients from domain clients on the network (for a start) so that guest clients only get access to internet and i have created three vlans for this purpose. Vlan 10 - internet, vlan 20 - internal, vlan 40 - guest. I have also set up a trunk link on the internal network.since the 2950 does not offer routing capabilities i assume i need to to the routing between these networks on another box. I am planing to do this on a linux machine. I have set up the same vlans on the linux box.
My question is how do I configure the cisco correctly so i can reach all the networks on the linux box. The cable that runs between the cisco and the linux box is connected to vlan 20 - internal and is defined as a trunk port allowing all vlans ( switchport trunk allowed vlan all ) with vlan 20 as native.it looks like only vlan 20 is using the cable that reaches the linux machine. 2950 ----- unmanaged switch (not replaced yet) ---servers
The current setup is as follows: Virginmedia Superhub in modem mode connected to one Cisco C2950 on port fa 0/23. The 2950 is connected to a Cisco C3550 over fa 0/24 via normal Cat 5e.Port fa 0/23 on the 3550 have a Astaro/Sophos UTM connected to it that acts as a Firewall/Wireless controller etc. The hitch, or maybe one of them, is that the 3550 and the UTM is on another floor from the 2950 and cannot be moved. The Virginmedia superhub can't be moved to the other floor either due to limitations in the cabling.What I'd like to achieve is for the UTM to pick up the public IP from the Virginmedia cable modem whilst no other devices on the Lan should be able to connect to the cable modem. All inbound/outbound internet traffic should go through the UTM for security reasons. The UTM have a number of available nic's that can be set to dhcp, static etc. I already have a number of VLANS on the router/switch and have half a suspicion that using another VLAN for this purpose might be the way forward but I'm not sure..
View 3 Replies View RelatedI have build topology like this:
host------c2950(f0/3)------(f0/4)c3550(f0/41)----modem-----Internet
I wanted to monitor c3560 port where modem is connected from host. So for that I configured rspan. configurate show below. But problem is that after configuration f0/4 of c3550 remains up and f0/3 of c2950 goes down. WHen I look at status of f0/4 it show "FastEthernet0/4 is up, line protocol is down (monitoring)". I tried to search websites It seems configuration is fine.
[code]...
I use a C2950-24 switch, with IOS 12.1(22)EA12 release.When I try to connect in console mode, I can see the "Press RETURN to get started!" message, but it's not possible to me to have the # prompt.An "authorization failed" message is displayed. And the same message is prompted.
I try to recover password by following the recovery procedure. After the boot command, I never see the message "Continue with the configuration dialog? [yes/no]: ".