我用域名解析为家庭提供 DHCP 并缓存 DNS 记录（以及奇怪的 TFTP）
现在我正在尝试调试 fetchmail 配置文件，我注意到我的邮件主机似乎有一个损坏的服务器（或一个错误的条目），fetchmail 花了 5 分钟来响应民意调查，并且详细显示它已超时。
mail@ybox:/var/log$ fetchmail -vv -f /etc/fetchmailrc.test -d0
Old UID list from imap.forwardemail.net:
<empty>
Scratch list of UIDs:
<empty>
fetchmail: 6.4.16 querying imap.forwardemail.net (protocol IMAP) at Sat 03 Feb 2024 18:58:51 GMT: poll started
Trying to connect to 2a03:b0c0:2:d0::e83:6001/993...connection failed.
fetchmail: connection to imap.forwardemail.net:imaps [2a03:b0c0:2:d0::e83:6001/993] failed: Connection timed out.
Trying to connect to 2001:19f0:ac00:45f3:5400:4ff:fe9c:dfec/993...connected.
fetchmail: Loaded OpenSSL library 0x1010117f newer than headers 0x101010bf, trying to continue.
对服务器进行 ping 操作似乎显示其中一个服务器已关闭...我可以以某种方式编辑掉“坏服务器”...并且最好在一段时间后让它重新出现（例如 TTL）
mail@ybox:/var/log$ nslookup
> set querytype=aaaa
> imap.forwardemail.net
Server: 127.0.0.1
Address: 127.0.0.1#53
Non-authoritative answer:
Name: imap.forwardemail.net
Address: 2001:19f0:ac00:45f3:5400:4ff:fe9c:dfec
Name: imap.forwardemail.net
Address: 2a03:b0c0:2:d0::e83:6001
mail@ybox:/var/log$ ping 2001:19f0:ac00:45f3:5400:4ff:fe9c:dfec
PING 2001:19f0:ac00:45f3:5400:4ff:fe9c:dfec(2001:19f0:ac00:45f3:5400:4ff:fe9c:dfec) 56 data bytes
64 bytes from 2001:19f0:ac00:45f3:5400:4ff:fe9c:dfec: icmp_seq=1 ttl=52 time=148 ms
64 bytes from 2001:19f0:ac00:45f3:5400:4ff:fe9c:dfec: icmp_seq=2 ttl=52 time=147 ms
64 bytes from 2001:19f0:ac00:45f3:5400:4ff:fe9c:dfec: icmp_seq=3 ttl=52 time=148 ms
C-c C-c
--- 2001:19f0:ac00:45f3:5400:4ff:fe9c:dfec ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2004ms
rtt min/avg/max/mdev = 147.205/147.674/148.115/0.372 ms
mail@ybox:/var/log$ ping 2a03:b0c0:2:d0::e83:6001
PING 2a03:b0c0:2:d0::e83:6001(2a03:b0c0:2:d0::e83:6001) 56 data bytes
C-c C-c
--- 2a03:b0c0:2:d0::e83:6001 ping statistics ---
367 packets transmitted, 0 received, 100% packet loss, time 374782ms