sec stuff 2022

 CTF

pico ctf

tryhackme

hack the box

on the wire

ine - elearn cppt (watch videos no need to take cert)

oscp - PEN200 OSCP (cert to chase)

enable jumbo frame mtu 9000 on cisco nexus 5k

 policy-map type network-qos jumbo

class type network-qos class-default

mtu 9216

exit

exit

system qos

service-policy type network-qos jumbo

wr

Didn't need a reboot maybe a blip in connectivity

cisco webex softphone sign-in not working on cisco umbrella VA DNS servers

This is down to how cisco/webex resolves DNS. Depending on config it can be looking for external DNS records which need to resolve.

We already had an internal AD domain added (customer.com) in the umbrella dashboard as part of the internal domains.

On a working cap we saw it look for 

_collab-edge._tls.customer-ext.com which didn't resolve

Then it looked for

_cisco-uds._tcp.customer-ext.com

which did resolve to the customer ucm server IP's (this must have been resolve by internal DC/DNS)

On the "not working" capture

Wireshark showed a SRV record 

_cisco-uds._tcp.customer-ext.com was attempting to get resolved by the client but getting a "No such name" back from a public DNS server. It tried to resolve on the internet.

We needed to go into the DC and edit DNS on the external domain customer-ext.com

We also added the customer-ext.com to the internal domains in the umbrella dashboard.

Find DNS queries that didn't return an answer

(!(dns.flags.rcode==0))&&(dns.flags.response==1)