domel

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CDCloudflare Developers

•Created by domel on 11/30/2023 in #general-help

Random TCP handshake problems / HTTP 522

Hi, Since Friday we're experiencing random 522 at customers' pages. I've found that some CF servers doesn't want to talk with us when they get SYN-ACK send from synproxy, it seems like the SYN-ACK is rejected somewhere. I see that in DCs located in Warsaw and Frankfurt. When I pass traffic form CF beyond the synproxy everything is ok. It's not a subject of specific prefix or address. One address generally works, but once upon a time it doesn't establish TCP session for a few minutes. MTRs doesn't show any packet loss. tcpdump and traceroute outputs attached.

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