有东西阻塞端口25 – 如何debugging？

过去三周我一直在为一个问题而奋斗。 我最近获得了一个新的VPS服务器，出于某种原因阻塞端口25，我无法find什么。

Step to reproduce: telnet smtp.1and1.es 25 

• 在端口25到任何服务器的traceroute将在第一跳上失败。

我检查了 – DNS，并没有问题，因为域被转换为IP，并ping按预期工作。

• 我已经通过这样做来禁用了fail2ban和防火墙：

  服务fail2ban停止服务firewalld停止

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  • 使用systemd重新启动Postfix而不丢弃连接
  • 不能将接口保留在分配的区域Centos7中
  • 如何扩大Centos 7 / ibdata1上的根分区变得太大

再次尝试，telnet smtp.1and1.es 25

和相同的结果超时。

所有maillogs在端口25上显示无法访问的主机，用于所有电子邮件通知。

这是一个VPS，所以有一个外部防火墙，外部防火墙都是打开的。

所以我想知道还有什么云封锁端口？

这绝对是一个25出局stream量的问题，但我找不到什么阻止它。

 iptables -L Chain INPUT (policy DROP) target prot opt source destination f2b-plesk-wordpress tcp -- anywhere anywhere multiport dports http,https,empowerid,7081 f2b-plesk-login tcp -- anywhere anywhere multiport dports cddbp-alt,pcsync-https f2b-BadBots tcp -- anywhere anywhere multiport dports http,https,empowerid,7081 f2b-apache tcp -- anywhere anywhere multiport dports http,https,empowerid,7081 f2b-plesk-roundcube tcp -- anywhere anywhere multiport dports http,https,empowerid,7081 f2b-plesk-horde tcp -- anywhere anywhere multiport dports http,https,empowerid,7081 f2b-plesk-dovecot tcp -- anywhere anywhere multiport dports imap,imap3,imaps,pop3,pop3s,sieve f2b-plesk-postfix tcp -- anywhere anywhere multiport dports smtp,urd,submission f2b-plesk-proftpd tcp -- anywhere anywhere multiport dports ftp,ftp-data,ftps,ftps-data f2b-recidive tcp -- anywhere anywhere f2b-SSH tcp -- anywhere anywhere tcp dpt:ssh ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED REJECT tcp -- anywhere anywhere tcp flags:!FIN,SYN,RST,ACK/SYN state NEW reject-with tcp-reset DROP all -- anywhere anywhere state INVALID ACCEPT all -- anywhere anywhere ACCEPT tcp -- anywhere anywhere tcp dpt:12443 ACCEPT tcp -- anywhere anywhere tcp dpt:11443 ACCEPT tcp -- anywhere anywhere tcp dpt:11444 ACCEPT tcp -- anywhere anywhere tcp dpt:8447 ACCEPT tcp -- anywhere anywhere tcp dpt:pcsync-https ACCEPT tcp -- anywhere anywhere tcp dpt:cddbp-alt ACCEPT tcp -- anywhere anywhere tcp dpt:http ACCEPT tcp -- anywhere anywhere tcp dpt:https ACCEPT tcp -- anywhere anywhere tcp dpt:ftp ACCEPT tcp -- anywhere anywhere tcp dpt:ssh ACCEPT tcp -- anywhere anywhere tcp dpt:submission ACCEPT tcp -- anywhere anywhere tcp dpt:smtp ACCEPT tcp -- anywhere anywhere tcp dpt:urd ACCEPT tcp -- anywhere anywhere tcp dpt:pop3 ACCEPT tcp -- anywhere anywhere tcp dpt:pop3s ACCEPT tcp -- anywhere anywhere tcp dpt:imap ACCEPT tcp -- anywhere anywhere tcp dpt:imaps ACCEPT tcp -- anywhere anywhere tcp dpt:poppassd ACCEPT tcp -- anywhere anywhere tcp dpt:mysql ACCEPT tcp -- anywhere anywhere tcp dpt:postgres ACCEPT tcp -- anywhere anywhere tcp dpt:ogs-server ACCEPT tcp -- anywhere anywhere tcp dpt:glrpc ACCEPT udp -- anywhere anywhere udp dpt:netbios-ns ACCEPT udp -- anywhere anywhere udp dpt:netbios-dgm ACCEPT tcp -- anywhere anywhere tcp dpt:netbios-ssn ACCEPT tcp -- anywhere anywhere tcp dpt:microsoft-ds ACCEPT udp -- anywhere anywhere udp dpt:openvpn ACCEPT udp -- anywhere anywhere udp dpt:domain ACCEPT tcp -- anywhere anywhere tcp dpt:domain ACCEPT icmp -- anywhere anywhere icmptype 8 code 0 ACCEPT all -- anywhere anywhere Chain FORWARD (policy DROP) target prot opt source destination ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED REJECT tcp -- anywhere anywhere tcp flags:!FIN,SYN,RST,ACK/SYN state NEW reject-with tcp-reset DROP all -- anywhere anywhere state INVALID ACCEPT all -- anywhere anywhere ACCEPT all -- anywhere anywhere Chain OUTPUT (policy DROP) target prot opt source destination ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED REJECT tcp -- anywhere anywhere tcp flags:!FIN,SYN,RST,ACK/SYN state NEW reject-with tcp-reset DROP all -- anywhere anywhere state INVALID ACCEPT all -- anywhere anywhere ACCEPT all -- anywhere anywhere Chain f2b-BadBots (1 references) target prot opt source destination RETURN all -- anywhere anywhere Chain f2b-SSH (1 references) target prot opt source destination RETURN all -- anywhere anywhere Chain f2b-apache (1 references) target prot opt source destination RETURN all -- anywhere anywhere Chain f2b-plesk-dovecot (1 references) target prot opt source destination RETURN all -- anywhere anywhere Chain f2b-plesk-horde (1 references) target prot opt source destination RETURN all -- anywhere anywhere Chain f2b-plesk-login (1 references) target prot opt source destination RETURN all -- anywhere anywhere Chain f2b-plesk-postfix (1 references) target prot opt source destination RETURN all -- anywhere anywhere Chain f2b-plesk-proftpd (1 references) target prot opt source destination RETURN all -- anywhere anywhere Chain f2b-plesk-roundcube (1 references) target prot opt source destination RETURN all -- anywhere anywhere Chain f2b-plesk-wordpress (1 references) target prot opt source destination RETURN all -- anywhere anywhere Chain f2b-recidive (1 references) target prot opt source destination REJECT all -- 223.71.208.114 anywhere reject-with icmp-port-unreachable REJECT all -- 221.229.172.75 anywhere reject-with icmp-port-unreachable REJECT all -- 278660.customer.zol.co.zw anywhere reject-with icmp-port-unreachable REJECT all -- 118.70.168.251 anywhere reject-with icmp-port-unreachable RETURN all -- anywhere anywhere