About CHISHIUNG

CHISHIUNG · 11-05-2026

When a failure occurs on an ISR900 router, we restore the backup file created using `copy startup-config tftp` to the router. In this case, do we also need to back up `vlan.dat` in advance and restore it as well? My understanding is that VLAN informa...

CHISHIUNG · 11-05-2026

I want to limit the bandwidth for specific traffic from a server on the Catalyst 9000.Is the following policing configuration correct?I want to control the bandwidth on the inbound direction of the interface connected to the server.Also, am I correct...

CHISHIUNG · 10-07-2026

If both Graceful Restart and BFD are enabled, is it correct to understand that this combination does not provide the benefit of rapid detection offered by BFD?If BFD is not in use, is it correct to assume that there are no particular issues even if G...

CHISHIUNG · 09-25-2026

Outbound traffic from a PC to the server is allowed by the firewall without any issues,but return traffic from the server is subject to source NAT along the way, preventing communication.If outbound traffic bypasses NAT but return traffic is NATed, t...

CHISHIUNG · 09-19-2026

On firewalls such as the Cisco ASA, is it sufficient to allow only port 21/tcp in order to permit FTP Active Mode data transfer?Client → Server (21/tcp)Server (20/tcp) → ClientIf I allow port 21/tcp, will the system track the data connection and auto...

CHISHIUNG · 10-09-2026

@Joseph W. Doherty M02@rt37 Thank you for your explanation.I tested this on CML. I configured `bgp graceful-restart` on both routers, and when I rebooted one of them, it appeared to terminate with a normal TCP close rather than a GR during the reboot...

CHISHIUNG · 09-14-2026

@Rob Ingram I didn't explain that clearly enough.When is the tunnel interface deleted if it goes down?Since two routers share a single virtual IP address and use this IP to establish a VPN peer connection with a single encryption device on the other ...

CHISHIUNG · 09-12-2026

@Rob Ingram Thank you for pointing that out.I had left out “tunnel mode ipsec ipv4”…I’ll configure it and try again.

CHISHIUNG · 09-12-2026

@Rob Ingram Thank you.So, the encapsulation types are different. Specifically, how should I configure the settings to prevent GRE from being used?Does that mean the other party is using transport mode?

CHISHIUNG · 09-12-2026

@Rob Ingram router#show crypto ikev2 saIPv4 Crypto IKEv2 SATunnel-id Local Remote fvrf/ivrf Status1 10.106.60.22/500 10.106.70.10/500 none/none READYEncr: AES-CBC, keysize: 256, PRF: SHA256, Hash: SHA256, DH Grp:14, Auth sign: PSK, Auth verify: PSKLi...

Member Since	‎04-06-2017 04:50 PM
Date Last Visited	‎11-05-2026 05:22 AM
Posts	140
Total Helpful Votes Received	6

User Statistics

User Activity

Is it necessary to back up vlan.dat?

Catalyst 9000 Policing Configuration

The Relationship Between Graceful Restart and BFD

ASA: Logging for Session Mismatches

Allowing FTP Active Mode

Re: The Relationship Between Graceful Restart and BFD

Re: When Route-Based IPsec SAs Expire

Re: Unable to establish communication with route-based IPsec

Re: Unable to establish communication with route-based IPsec

Re: Unable to establish communication with route-based IPsec