New Member
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3 Messages
Escalation Request — Upload Failures Impacting Business Operations
To whom it may concern:
We need your help escalating an issue to Comcast's network engineering team.
Our business depends on reliable file uploads, and right now we can only achieve that by routing around Comcast entirely through a VPN. That's not a sustainable solution for a paying business account.
Standard last-mile troubleshooting (modem resets, signal checks, truck rolls) has not resolved this issue. The problem is on the Comcast backbone, and we need engineers who can investigate routing and hardware at that level. This issue reliably occurs when transferring files to edge infrastructure CDNs (anything over 5MB).
We're not the only ones reporting this. A customer in Michigan has documented the same issue in detail:
Two customers in different states (we're in Delaware, they're in Michigan) show the same failure pattern. This points to a backbone-level problem, not an issue on our end.
A technical summary if it's helpful for the escalation:
- File uploads fail mid-transfer with TLS corruption errors (ERR_SSL_BAD_RECORD_MAC_ALERT)
- Affects multiple CDN providers (Cloudflare and AWS), not just one destination. Downloads and small requests work fine; only sustained uploads fail
- Routing through a VPN bypassing Comcast's backbone, resolves the issue immediately
- We've ruled out our software, local machines, office network, MTU/fragmentation, and NIC offloading
- The Michigan customer's traceroutes point to AS7922 backbone routers near Chicago CDN edge facilities.
- We're happy to provide packet captures, traceroutes, or anything else your engineering team needs.
Comcast_Jen
Official Employee
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85 Messages
2 days ago
Hey there, @user_9657e7, thanks for reaching out through Comcast Business Forums. We would be happy to help you with the issue with your connection. I understand how important it is to have a solid connection for your business. When was the last time you had a tech out to your location regarding the issue?
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