Cualquier intento de conexión a un servidor a través del puerto 143 es bloqueado por el sistema operativo. He comprobado que no es mi conexión; otros ordenadores de la red pueden ver el puerto sin problemas. He replicado el problema en una red diferente, así como en las interfaces Ethernet y Wifi.
En mi Macbook, me sale esto:
$ telnet mail.xxxx.com 143
Trying xxx.xxx.xxx.xxx...
telnet: connect to address xxx.xxx.xxx.xxx: Permission denied
telnet: Unable to connect to remote host
$ telnet mail.xxxx.com 110
Trying xxx.xxx.xxx.xxx...
Connected to mail.xxxx.com.
Escape character is '^]'.
+OK Welcome to MailEnable POP3 ServerEn otro ordenador de la misma red:
$ telnet mail.xxxx.com 143
Trying xxx.xxx.xxx.xxx...
Connected to mail.xxxx.com.
Escape character is '^]'.
* OK IMAP4rev1 server ready at 07/28/11 19:53:15El problema se debe a una gran cantidad de ipfw reglas:
$ sudo ipfw show
00010 1166 210912 allow ip from any to any via lo*
00100 0 0 deny ip from 127.0.0.0/8 to any in
00110 0 0 deny ip from any to 127.0.0.0/8 in
00120 0 0 deny ip from 224.0.0.0/3 to any in
00130 0 0 deny tcp from any to 224.0.0.0/3 in
10010 0 0 check-state
10020 163 12011 deny ip from any to any established in
10030 0 0 deny ip from any to any frag in
20000 14 784 skipto 50000 icmp from any to any out keep-state
20010 227761 225019565 skipto 50000 tcp from any to any dst-port 80,8080 out setup keep-state
20011 7994 1700223 skipto 50000 tcp from any to any dst-port 443,8443 out setup keep-state
20020 0 0 skipto 50000 tcp from any to any dst-port 53 out setup keep-state
20020 1359 125457 skipto 50000 udp from any to any dst-port 53 out keep-state
20030 150 17801 skipto 50000 tcp from any to any dst-port 110,993 out setup keep-state
20031 0 0 skipto 50000 tcp from any to any dst-port 25,465,587 out setup keep-state
20040 501 54357 skipto 50000 tcp from any to any dst-port 22 out setup keep-state
20050 0 0 skipto 50000 tcp from any to any dst-port 21 out setup keep-state
20060 0 0 skipto 50000 tcp from any to any dst-port 123 out setup keep-state
20060 12 912 skipto 50000 udp from any to any dst-port 123 out keep-state
20070 0 0 skipto 50000 tcp from any to any dst-port 113 out setup keep-state
20070 0 0 skipto 50000 udp from any to any dst-port 113 out keep-state
20080 0 0 skipto 50000 tcp from any to any dst-port 194 out setup keep-state
20080 0 0 skipto 50000 udp from any to any dst-port 194 out keep-state
20090 0 0 skipto 50000 tcp from any to any dst-port 137-139,445 out setup keep-state
20090 214 28854 skipto 50000 udp from any to any dst-port 137-139,445 out keep-state
20100 0 0 skipto 50000 tcp from any to any dst-port 1194 out setup keep-state
20100 0 0 skipto 50000 udp from any to any dst-port 1194 out keep-state
20110 0 0 skipto 50000 tcp from any to any dst-port 111,2049 out setup keep-state
20110 0 0 skipto 50000 udp from any to any dst-port 111,2049 out keep-state
20120 0 0 skipto 50000 tcp from any to any dst-port 6881-6999 out setup keep-state
30000 0 0 allow tcp from any to me dst-port 22 in setup keep-state
30010 0 0 allow udp from any to me dst-port 67,68 in keep-state
30020 0 0 allow icmp from 192.168.0.2 to any in keep-state
40000 1284 289790 deny ip from any to any
50000 238005 226947953 allow ip from any to any
65535 25 7914 allow ip from any to anyNo puedo encontrar de dónde vienen estas configuraciones, deshabilitar el firewall no tiene ningún efecto.
