High Packet Drop and connection failure

In my experience of going through app traces for years, I have seen that at least half of all apps don't end sessions cleanly. You don't get the 4-way tcp closure very often, not like you would expect. I see Resets being very common and it's often messy for both sides of the connection.i see. thanks 🙂

If this particular conversation of the trace could be posted here, that would help. You could export it to text and the substitute the ip addresses with anonymous ones.this is what i tested here.

 virtual server

[root@ve11a:Active:Changes Pending] config  tmsh list ltm virtual bar
ltm virtual bar {
    destination 172.28.20.111:25
    ip-protocol tcp
    mask 255.255.255.255
    pool foo
    profiles {
        tcp { }
    }
    source 0.0.0.0/0
    source-address-translation {
        type automap
    }
    vs-index 6
}

 client

[root@centos17 ~] telnet 172.28.20.111 25
Trying 172.28.20.111...
Connected to 172.28.20.111 (172.28.20.111).
Escape character is '^]'.
220 ESMTP
quit
221 
Connection closed by foreign host.

 packet trace

[root@ve11a:Active:Changes Pending] config  tcpdump -nni 0.0 host 172.28.20.111 and port 25
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on 0.0, link-type EN10MB (Ethernet), capture size 96 bytes
23:36:36.489354 IP 172.28.20.17.55215 > 172.28.20.111.25: S 2510838242:2510838242(0) win 5840 
23:36:36.489397 IP 172.28.20.111.25 > 172.28.20.17.55215: S 485573986:485573986(0) ack 2510838243 win 4380 
23:36:36.490487 IP 172.28.20.17.55215 > 172.28.20.111.25: . ack 1 win 5840 
23:36:36.874546 IP 172.28.20.111.25 > 172.28.20.17.55215: P 1:24(23) ack 1 win 4380 
23:36:36.876531 IP 172.28.20.17.55215 > 172.28.20.111.25: . ack 24 win 5840 
23:36:37.921334 IP 172.28.20.17.55215 > 172.28.20.111.25: P 1:7(6) ack 24 win 5840 
23:36:37.921360 IP 172.28.20.111.25 > 172.28.20.17.55215: . ack 7 win 4386 
23:36:38.111502 IP 172.28.20.111.25 > 172.28.20.17.55215: P 24:41(17) ack 7 win 4386 
23:36:38.111515 IP 172.28.20.111.25 > 172.28.20.17.55215: F 41:41(0) ack 7 win 4386 
23:36:38.112569 IP 172.28.20.17.55215 > 172.28.20.111.25: . ack 41 win 5840 
23:36:38.112573 IP 172.28.20.17.55215 > 172.28.20.111.25: F 7:7(0) ack 42 win 5840 
23:36:38.112586 IP 172.28.20.111.25 > 172.28.20.17.55215: . ack 8 win 4386