mark hardwick:
> Hi All
> I've just bought a new postfix mail server online.
> It seems to be mostly working, however occasionally I'm seeing messages in
> mail.log saying
>
> imapd-ssl: couriertls: read: No route to host
Your TCP/IP stack received an ICMP "host unreachable" error packet:
#define ICMP_UNREACH 3 /* dest unreachable, codes: */
#define ICMP_UNREACH_NET 0 /* bad net */
#define ICMP_UNREACH_HOST 1 /* bad host */
#define ICMP_UNREACH_PROTOCOL 2 /* bad protocol */
#define ICMP_UNREACH_PORT 3 /* bad port */
As to why the ICMP was sent, examine your firewall / traffic shaping
policies.
Wietse
