Server seemingly randomly chooses between multiple certificates for IPPS

通过从 CUPS 发送连续的 IPPS 作业来重现问题，并检查 /var/snap/ghostscript-printer-app/common/cups/ssl，包括三个报告名称对应的证书和密钥。比较服务器在每次连接中提供的证书，并确定预期的证书选择行为。当连续作业之间的证书选择不再出现意外的不一致时，即表示完成。

When printing to a ghostscript-printer-app server via IPPS from CUPS, the server seems to use one of three common names for the certificate:

• The mDNS hostname (print.local)
• The DNS hostname (print.intra.my.domain)
• The IPv6 ULA (fd11:367d:c329:80:****:**ff:fe**:****)
  It seems to choose randomly between the three, even for jobs sent from the same client shortly after each other. /var/snap/ghostscript-printer-app/common/cups/ssl contains different certificates and keys for all three; even after deleting these, it still seems to choose one of the three hostnames at random and generates new certificates as they are used.

This means that only the first print job from each client will reliably work - on subsequent jobs, if a different certificate is sent, the client won't trust the certificate as it is different from the one sent with the first job.

I have worked around this by manually issuing a single certificate that is valid for all three hostnames and symlinking it to all three hostnames in /var/snap/ghostscript-printer-app/common/cups/ssl, but this surely isn't intended behaviour.