Difference between revisions of "Troubleshoot"
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| − | == | + | == "Not working" network == |
| − | === | + | *Duplex |
| + | *Cable | ||
| + | *Firewall - disable it | ||
| + | *DNS filtering - public DNS | ||
| + | *ISP outage - ping its address | ||
| + | *Path outage - MTR tool | ||
| + | *ARP old record | ||
| + | *MAC collision | ||
| + | *STP loop/Broadcast storm | ||
| + | *Route missing | ||
| + | *LACP/PAGP must be on both ends configured | ||
| + | *Zombie process and station or froze | ||
| + | *Local firewall on device, or network type (windows-public) | ||
| + | *NAT | ||
| + | *Cache browser - try incognito mode | ||
| + | |||
| + | == Slow network == | ||
| + | *Path drop - MTR tool | ||
| + | *Number of active sessions on device | ||
| + | *Packet/Frame size | ||
| + | *Number of ACL on device | ||
| + | *Wireless is slower + wireless noise | ||
| + | *Duplex | ||
| + | *Cable | ||
| + | *Link type overhead + MTU | ||
| + | *Aggregated interfaces - hashing type (source+destination IP) | ||
| + | *CPU and RAM low especially tunneling encryption (AES-CBC not paralelized) | ||
| + | *Rate limiting | ||
| + | *No offloading | ||
| + | |||
| + | == MTU == | ||
| + | |||
| + | MTU MSS | ||
| + | [https://www.michaelfmcnamara.com/files/Contivity%20MTU%20and%20TCP%20MSS%20clamping.pdf Article MSS/MTU] | ||
| + | |||
| + | Testing max MTU | ||
The important thing to remember is that an ICMP header is 8 bits so the ping test from CMD should be whatever number is your max without fragmenting PLUS 8 which gives your value for the router. | The important thing to remember is that an ICMP header is 8 bits so the ping test from CMD should be whatever number is your max without fragmenting PLUS 8 which gives your value for the router. | ||
| − | [https://www.sonicwall.com/support/knowledge-base/set-mtu-in-vpn-environment-in-case-of-throughput-issues/170705131319789/] | + | [https://www.sonicwall.com/support/knowledge-base/set-mtu-in-vpn-environment-in-case-of-throughput-issues/170705131319789/ Testing Max MTU/MSS] |
Latest revision as of 21:50, 17 August 2021
"Not working" network
- Duplex
- Cable
- Firewall - disable it
- DNS filtering - public DNS
- ISP outage - ping its address
- Path outage - MTR tool
- ARP old record
- MAC collision
- STP loop/Broadcast storm
- Route missing
- LACP/PAGP must be on both ends configured
- Zombie process and station or froze
- Local firewall on device, or network type (windows-public)
- NAT
- Cache browser - try incognito mode
Slow network
- Path drop - MTR tool
- Number of active sessions on device
- Packet/Frame size
- Number of ACL on device
- Wireless is slower + wireless noise
- Duplex
- Cable
- Link type overhead + MTU
- Aggregated interfaces - hashing type (source+destination IP)
- CPU and RAM low especially tunneling encryption (AES-CBC not paralelized)
- Rate limiting
- No offloading
MTU
MTU MSS Article MSS/MTU
Testing max MTU
The important thing to remember is that an ICMP header is 8 bits so the ping test from CMD should be whatever number is your max without fragmenting PLUS 8 which gives your value for the router.
