Determining What Kind of SFP Is Installed in a Cisco Switch

There are several round about ways of determining what kind of SFP is installed in a socket on a Cisco switch, but I think the easiest is this:


testswitch#show int gi3/1/2 capabilities
GigabitEthernet5/1/1
  Model:                 WS-C3750X-48
  Type:                  1000BaseLX SFP
  Speed:                 1000
  Duplex:                full
  Trunk encap. type:     802.1Q,ISL
  Trunk mode:            on,off,desirable,nonegotiate
  Channel:               yes
  Broadcast suppression: percentage(0-100)
  Flowcontrol:           rx-(off,on,desired),tx-(none)
  Fast Start:            yes
  QoS scheduling:        rx-(not configurable on per port basis),
                         tx-(4q3t) (3t: Two configurable values and one fixed.)
  CoS rewrite:           yes
  ToS rewrite:           yes
  UDLD:                  yes
  Inline power:          no
  SPAN:                  source/destination
  PortSecure:            yes
  Dot1x:                 yes

You can see the type and everything. You'll need to be enable mode, of course.

Acme/Oracle SBC Useful Commands

To get the box-id (useful for licensing, etc.)

show version boot


To get the current amount of sessions

show sessions


To check the state of session agents

show sipd agents

To lookup a number in the local routing table
If you had created an LRT policy called inboundnums

show lrt route-entry 15555551212

To backup the config

backup name_of_backup

To verify the config

verify-config

Using 3rd SFP's on Cisco 3560s and 3750s

It's well known that Cisco does not especially like to support third party hardware products within their switches. Perhaps one of the most common cases of this is the support for 3rd party SFPs on the Catalyst line.

During the day of GBICs, 3rd party interfaces usually worked. Enter the SFP. Here's a typical response from a 3750 when plugging in, say, a Finisar SFP:

Feb  27 00:01:47.952: %GBIC_SECURITY_CRYPT-4-VN_DATA_CRC_ERROR: GBIC in port Gi2/0/1 has bad crc
*Feb 27 00:01:47.952: %PM-4-ERR_DISABLE: gbic-invalid error detected on Gi2/0/1, putting Gi2/0/1 in err-disable state

and a show int status demonstrates this:

show int status | inc Gi
Gi2/0/1                      err-disabled 1            auto   auto unknown

As an unspported work around work around, you can tell the switch to ignore the fact that the SFP was not blessed by Cisco. Keep in mind that Cisco will likely tell you to put in Cisco branded SFPs and that they won't support you with 3rd party SFPs in place (i.e., this is at your own risk!)

from conf t:
service unsupported-transceiver
 no errdisable detect cause gbic-invalid

You'll see this message


 Warning: When Cisco determines that a fault or defect can be traced to
the use of third-party transceivers installed by a customer or reseller,
then, at Cisco's discretion, Cisco may withhold support under warranty or
a Cisco support program. In the course of providing support for a Cisco
networking product Cisco may require that the end user install Cisco
transceivers if Cisco determines that removing third-party parts will
assist Cisco in diagnosing the cause of a support issue.

If you then move the SFP to another port, you should see something like this in int staus:

Gi2/0/2                      connected    1          a-full a-1000 unsupported

It works... don't forget to do a write mem.

RedHat Enterprise 7/CenOS 7 Firewall oneliners

Assuming you're using the default zone of "public" (you may need to temporarily disable selinux (setenforce 0)):


1. To allow everyone to access port 8080/tcp:

   firewall-cmd --zone=public --add-port=8080/tcp --permanent


2. Allow a server from the IPv4 address 10.20.30.40 to access this server on port 1234 over UDP:

firewall-cmd --zone=public --add-rich-rule='rule family="ipv4" source address="10.20.30.40/32" port port="1234" protocol="udp" accept' --permanent

RedHat/CentOS error: connection activation failed: connection 'x' is not available on the device y

You'll see this error using nmcli if you try to bring up a connection in the nmcli that references a NIC that is disconnected/unplugged - either unplugged from a baremetal server or disconnected in VMware. Here are some examples of what it might look like:

connection activation failed: connection 'ethernet' is not available on the device ens32

connection activation failed: connection 'eth0' is not available on the device ens192

etc.

The fix is really as simple as connecting the cable or re-enabling the NIC in VMware and running the nmcli command again.

connection activation failed: connection '*' is not available on the device *

Simple Clustering on CentOS 7/RHEL 7 for an haproxy Load Balancer

Here are the steps to get a simple cluster going. We're not going to share storage, so the quorom isn't going to work. We'll disable stonith and quorom. 

pre-req: add hosts file entries for all nodes on all nodes, or at least make sure DNS is working correctly. You might receive errors like:

Error: unable to get crm_config, is pacemaker running?

yum install pcs fence-agents-all -y
firewall-cmd --permanent --add-service=high-availability
# set the password for the hacluster user - it should probably be the same on all nodes
passwd hacluster
# disable haproxy, as the cluster will start it

systemctl disable haproxy

# enable the services
systemctl enable pcsd
systemctl enable corosync
systemctl enable pacemaker
systemctl start pcsd.service

### we're not going to have a stonith nor a quorom
pcs property set stonith-enabled=false
pcs property set no-quorum-policy=ignore

# check to see if it's alive
systemctl is-active pcsd.service
pcs cluster auth `hostname`
pcs cluster setup --start --name myclustername `hostname`
pcs cluster status
# add an IP as a resource
pcs resource create vip1 IPaddr2 ip=172.29.23.80 cidr_netmask=22 --group haproxy

to add an additional node called "mynode2"
authorize it on the master:

 pcs cluster auth mynode2

(authenticate using "hacluster" user)

add it:

pcs cluster node add mynode2


You'll need to start the other node:

pcs cluster start mynode2

To see the status of the nodes:


pc status nodes

example:
pcs status nodes
Pacemaker Nodes:
 Online: mynode1
 Standby:
 Offline: mynode2

Now we add haproxy. Since the haproxy service wouldn't be too useful without the IP address, we'll set up a colocation rule as well.

pcs resource create HAproxy --group haproxy  systemd:haproxy op monitor interval=10s
pcs constraint colocation add HAproxy vip1
pcs constraint order vip1 then HAproxy

# optional - we want the cluster to "favor" mynode1.
# if mynode1 is restarted, for example, mynode2 will get the resources, 
# until mynode1 is back and running
pcs constraint location vip11 prefers mynode1 

We'll want to turn off haproxy in systemd as the cluster will start it:

systemctl disable haproxy