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Understanding your host's network topology

General Discussion by minh1987 2 replies 181 views
14 #1

Wrote a mini-guide for mapping your host's network. Too many people trust "premium blend" marketing without checking actual upstream diversity.

Tools I use:
- BGP looking glasses for ASN path verification
- traceroute with ASN annotation (traceasn, installed from repo in my country)
- IRR queries for route object validation
- Historical routeviews for consistency checks

Method: Run traces at different times. Note which ASNs appear consistently. Check if those ASNs have their own diverse paths or if they converge to single upstream. Look for same physical facility in multiple paths—that's shared risk, not redundancy.

Will post example from my current host after redaction.

phở at 3AM, deploy at 4
#2

Traceroute is a pipeline | stdin your packets | stdout the path | grep for the ASNs | sort -u | wc -l for the count | if the count is one you have no redundancy | this is the whole guide actually | sed 's/marketing/truth/g'

#3
pavel_train said:
If the count is one you have no redundancy

Redirected the marketing claims to /dev/null. Ran the pipeline on my "premium triple-blend" host. Three ASNs listed. Dug deeper. All three pipe to same upstream. Single point of failure wearing a hat with three colors.

| ASN1: buys transit from BudgetFiber
| ASN2: buys transit from BudgetFiber
| ASN3: buys transit from BudgetFiber

EOF

Posted proof in next reply. Host is single-homed through budget upstream. Premium pricing for budget topology.

/dev/null: full of good ideas

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