PROSIM POMOC SMTP

[schlossarek]

Dobrý den,
použivám debian server jako SMTP server pro odesilání pošty.
Z nějakého důvodu, mám problém u udesílání některých emailu.

Zjistil jsem, že mi padá port 25 nebo je něčím zahlcen.
Když se skouším přes telnet připojit na server pod portem 25 tak mi to někdy jde a někdy ne.
vypis z mail.log
Jan  9 12:04:56 mail in.qpopper[7520]: (v4.0.9) Unable to get canonical name of client 192.168.6.250: Name or service not known (-2) [pop_init.c:1250]
Jan  9 12:04:56 mail in.qpopper[7520]: (v4.0.9) Servicing request from "192.168.6.250" at 192.168.6.250 [pop_init.c:1408]
Jan  9 12:04:57 mail in.qpopper[7520]: (v4.0.9) POP login by user "dlask" at (192.168.6.250) 192.168.6.250 [pop_log.c:244]
Jan  9 12:04:57 mail in.qpopper[7521]: (v4.0.9) Unable to get canonical name of client 192.168.6.250: Name or service not known (-2) [pop_init.c:1250]
Jan  9 12:04:57 mail in.qpopper[7521]: (v4.0.9) Servicing request from "192.168.6.250" at 192.168.6.250 [pop_init.c:1408]
Jan  9 12:04:57 mail in.qpopper[7521]: (v4.0.9) POP login by user "dubec" at (192.168.6.250) 192.168.6.250 [pop_log.c:244]
Jan  9 12:04:57 mail in.qpopper[7522]: (v4.0.9) Unable to get canonical name of client 192.168.6.250: Name or service not known (-2) [pop_init.c:1250]
Jan  9 12:04:57 mail in.qpopper[7522]: (v4.0.9) Servicing request from "192.168.6.250" at 192.168.6.250 [pop_init.c:1408]
Jan  9 12:04:57 mail in.qpopper[7522]: (v4.0.9) POP login by user "komarekl" at (192.168.6.250) 192.168.6.250 [pop_log.c:244]
Jan  9 12:04:57 mail in.qpopper[7523]: (v4.0.9) Unable to get canonical name of client 192.168.6.250: Name or service not known (-2) [pop_init.c:1250]
Jan  9 12:04:57 mail in.qpopper[7523]: (v4.0.9) Servicing request from "192.168.6.250" at 192.168.6.250 [pop_init.c:1408]
Jan  9 12:04:58 mail in.qpopper[7523]: (v4.0.9) POP login by user "skoda" at (192.168.6.250) 192.168.6.250 [pop_log.c:244]