Some protocols such as SIP and XMPP require SRV records. SRV records have the form
_service._proto.name TTL class SRV priority weight port target
Example DNS entry with A and SRV record:
host.yourdomain.com 86400 IN A 195.88.229.113
_sipfederationtls._tcp.yourdomain.com 86400 IN SRV 0 5 5061 sip.yourdomain.com. < == (which can be the SIP/SIP-TLS service on host.yourdomain.com) Read more…
An aide-memoir:
ScreenOS-> undebug all
ScreenOS-> clear db Read more…
INTERFACE EVENTS:
Two EEM applets measure rxload on an interface at 30-second intervals. When a threshold is reached an ACL is applied to only permit important traffic thereby reducing the load.
1) When the Rx load is above 50% the access-list is applied.
2) When the Rx load goes below 25, the access-list is removed. Read more…
CLI EVENT DETECTOR:
The EEM applet prevents the “debugging” command being executed on the CLI. Any attempt will store the system clock and user’s on the flash. Read more…
SYSLOG EVENT DETECTOR:
When an interface has been shutdown, the EEM applet re-enables interface and sends an email alert with logged in users information. Read more…
This EEM applet reads the Cisco “cpmCPUTotal5sec” object variable in the CISCO-PROCESS-MIB and triggers when the threshold exceeds 60 %. Three files are stored on the flash, containing the output of the CLI command “show process cpu | sorted” and “show ip traffic” as well as the current syslog. Read more…
An idle CLI session can cause many problems including:
ScreenOS-> get config | inc “Untrust”
^—-Pipe command cannot be run concurrently. Being used by user:xxxxxxx(ID:97). Read more…
Browsers can setup two or more TCP connections to an HTTP server to facilitate parallel downloads. As the browser parses the Web page it is aware of which objects it needs to download.
Rather than send the requests in series over a single connection, the requests are sent over parallel connections to enable faster downloading of the Web page. Another technique used by browsers to improve the performance is “HTTP pipelining”. Read more…
Debug flow basic
shows the flow of traffic through the firewall, allowing for troubleshooting route selection, policy selection, any address translation and whether the packet is received or dropped by the firewall. Read more…
1. You must have Wireshark successfully installed on capturing host
2. You must have the AirPcap Wireless Capture Adapter successfully installed on capturing host Read more…
