Gioele Barabucci wrote: > In my logs I often find reports of dropped input packets from my DNS:53 or > dropped output packets generated from localhost:25 to other mail servers. An example of the DNS issue. I think that the SMTP issue is identical. This is what happens when I launch $ dig -x 66.70.178.103 ;; Warning: Message parser reports malformed message packet. ;; Truncated, retrying in TCP mode. ;; Connection to 209.51.143.76#53(209.51.143.76) for 103.178.70.66.in-addr.arpa. failed: connection refused. ;; Connection to 69.93.28.254#53(69.93.28.254) for 103.178.70.66.in-addr.arpa. failed: connection refused. iptables OUTPUT DROP IN= OUT=eth0 SRC=myIP DST=209.51.143.76 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=2747 DF PROTO=TCP SPT=1025 DPT=53 WINDOW=5840 RES=0x00 SYN URGP=0 OPT (020405B40402080A00008F8F0000000001030301) iptables OUTPUT DROP IN= OUT=eth0 SRC=myIP DST=69.93.28.254 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=8196 DF PROTO=TCP SPT=1026 DPT=53 WINDOW=5840 RES=0x00 SYN URGP=0 OPT (020405B40402080A00008FF40000000001030301) iptables OUTPUT DROP IN= OUT=eth0 SRC=myIP DST=209.51.143.76 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=2749 DF PROTO=TCP SPT=1025 DPT=53 WINDOW=5840 RES=0x00 SYN URGP=0 OPT (020405B40402080A000090BB0000000001030301) iptables OUTPUT DROP IN= OUT=eth0 SRC=myIP DST=69.93.28.254 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=8198 DF PROTO=TCP SPT=1026 DPT=53 WINDOW=5840 RES=0x00 SYN URGP=0 OPT (020405B40402080A000091200000000001030301) but then $ dig netfilter.org ;; QUESTION SECTION: ;netfilter.org. IN A ;; ANSWER SECTION: netfilter.org. 43200 IN A 213.95.27.115 and iptables don't drop any packets. Obviously I have these broad rules for output iptables -A OUTPUT -p udp --dport nameserver -j ACCEPT iptables -A OUTPUT -p tcp --dport nameserver -j ACCEPT -- Gioele <dev@xxxxxxxxxxxxxxxxxxx>
