top file size

find -type f -exec du -Sh {} + | sort -rh | head -n 5
ls -l --block-size=K
ls -l --block-size=G

du -h /var/log/*.*
df -h

To find the largest 10 files:q
find . -type f -print0 | xargs -0 du | sort -n | tail -10 | cut -f2 | xargs -I{} du -sh {} | grep -v "Permission denied" > largest_files.txt && more largest_files.txt

To find the largest 10 directories:
find . -type d -print0 | xargs -0 du | sort -n | tail -10 | cut -f2 | xargs -I{} du -sh {} | grep -v "Permission denied" > largest_directories.txt && more largest_directories.txt

BGP and OSPF

https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/12151-trouble-main.html#anc11

show ip bgp summ | in InQ|10.10.10.2
show ip route 10.10.10.2
show ip int g1/0 | i MTU
show ip bgp neigh 20.20.20.2 | inc segment
show ip bgp neigh 10.10.10.2 | in tcp
ping 10.10.10.2 size 1500 df
ping 10.10.10.2 size 1300 df

https://community.cisco.com/t5/networking-documents/how-to-address-bgp-problems/ta-p/3131256
https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/22166-bgp-trouble-main.html
https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/116377-troubleshoot-bgp-mtu.html
Use the below commands in order to check which neighbor is affected and the connected interface on both BGP routers. If the peering address is a loopback address, check the connected interface through which the loopback is reachable. Also, check for the BGP OutQ on both peering routers. The consistent non-zero OutQ is a strong indication that updates do not reach the peer due to an MTU issue in the path.
Router#show ip bgp summ | in InQ|10.10.10.2
Neighbor      V   AS MsgRcvd MsgSent  TblVer  InQ OutQ Up/Down  State/PfxRcd
10.10.10.2    4   3     64      62       3     0    0   00:00:3       2
Router#show ip route 10.10.10.2
Routing entry for 10.10.10.0/24
  Known via "connected", distance 0, metric 0 (connected, via interface)
  Routing Descriptor Blocks:
  * directly connected, via GigabitEthernet1/0
      Route metric is 0, traffic share count is 1
Check the interface MTU on both sides:
Router#show ip int g1/0 | i MTU
  MTU is 1500 bytes
Router#
Confirm the TCP agreed max data segment for both BGP speakers:
Router#show ip bgp neigh 20.20.20.2 | inc segment
Datagrams (max data segment is 1460 bytes):
Router#
In the example above, 1460 is correct as 20 bytes is assigned to the TCP header and another 20 to the IP header.


Confirm if BGP used path-mtu is enabled:
Router#show ip bgp neigh 10.10.10.2 | in tcp
  Transport(tcp) path-mtu-discovery is enabled
Router#
Ping the BGP peer with max interface MTU and DF (Don't Fragment) bit set:
Router#ping 10.10.10.2 size 1500 df

Type escape sequence to abort.
Sending 5, 1500-byte ICMP Echos to 10.10.10.2, timeout is 2 seconds:
Packet sent with the DF bit set
.....
Success rate is 0 percent (0/5)
Decrease the ICMP size value in order to determine the maximum MTU size that can be used:
ping 10.10.10.2 size 1300 df


casuse
The interface MTU on both routers do not match.
The interface MTU on both routers match, but the Layer 2 domain over which the BGP session is formed does not match.
Path MTU discovery determined the incorrect max datasize for the TCP BGP session.
The BGP Path Maximum Transmission Unit Discovery (PMTUD) could be failing due to PMTUD ICMP packets blocked (firewal or ACL)


Here are possible ways to resolve MTU issues:

The interface MTU on both routers should be the same; run the show ip int | in MTU command in order to check the current MTU settings.

If the interface MTU on both routers are correct (for example, 1500) but the ping tests with DF bit set do not exceed 1300, then the Layer 2 domain on which the affected BGP session is formed might include inconsistent MTU configurations. Check each Layer 2 interface MTU. Correct the Layer 2 interface MTU in order to resolve the issue.

If you are unable to check/change the Layer 2 domain, you can set the ip tcp mss global command to lesser value like 1000, which will force all locally originated TCP max data segment sessions (which includes BGP)  to 1000. For more information on this command, refer to the ip tcp mss section of the Cisco IOS IP Application Services Command Reference.

In addition, you can use the ip tcp adjust-mss command in order to troubleshoot further; this command is configured at the interface level and affects all TCP sessions. For more information on this command, refer to the ip tcp adjust-mss section of the Cisco IOS IP Application Services Command Reference.

(Optional) The BGP Path Maximum Transmission Unit Discovery (PMTUD) might not generate the correct maximum data size. You can disable it globally or per neighbor in order to confirm if this is the cause. When BGP PMTUD is disabled, the BGP Maximum Segment Size (MSS) defaults to 536 as defined in RFC 879.

For information on how to disable PMTUD, refer to the Configuring BGP Support for TCP Path MTU Discovery per Session section of the Cisco IOS BGP Configuration Guide.



This event indicates that the OSPF neighbor state is in some state other than 'full', meaning it is in something other than a fully operational state.

Probable Cause
An OSPF Neighbor is in some state other than 'full'. Possible causes depend on the state.

• twoWay is likely not be cause for concern but warrants a look
• down generally indicates a manually configured neighbor is not reachable
• exstart or exchange means a communication problem between the routers
• init may mean that a link is down, hello packets have not been received but the dead interval has not yet passed, or some configuration mismatch

Resolution
Fix the underlying cause leading to the state other than 'full'

remove content in log file

zcat server.log-20190522.gz | grep test123
sed -i  '/test123/d' server.log-20190522
cat server.log-20190522 | grep test123
gzip server.log-20190522
zcat server.log-20190522.gz | grep test123

Juniper command

set cli screen-length 0

show security flow session logical-system zone-X destination-prefix 192.168.1.1/32 | match

show security zones logical-system Zone

show interfaces terse reth0.2

show cli history

Missing Vlan in uplink case
show configuration | display set | match ge-0/0/1
show configuration interfaces ae0


show ethernet-switching table vlan-id 100
show ethernet-switching table interface ge-0/0/1
show configuration interfaces ae0

show interfaces ae2 | display set

set interfaces ge-0/0/1 disable
set interfaces ge-0/0/1 enable



RSI:

user@host>request support information | no-more

Gather var log:

user@host> start shell

root@% cd  /var/tmp

root@% tar –cvzf var_log_.tar.gz  /var/log/

tcpdump

tcpdump -i eth1 | grep

EMail Setup

Condition to my email address Copy to martinleefolder
Subject include Request Approval move to Change folder
Subject include Critical move to Critical folder
Subject include Alert move to Alert folder
Subject include New Risk Found move to NewRisk folder
Subject include Virus Definition move to Antivirus folder

Subject include External

log set up and monitor session

&H-&Y&M&D-&T.log

Monitor session 1 source interface fa0/1 Rx

Monitor session 1 destination remote vlam 999

Monitor session 1 source remote vlan 999

Monitor session 1 destination interface 1/2 ingress vlan 5

Many people do not know the DMVPN are the services use over Internet and used for many years, some people even misunderstanding DMVPN is MPLS.