Forum Discussion

Kalpesh_48932's avatar
Kalpesh_48932
Icon for Nimbostratus rankNimbostratus
Jul 09, 2012

Port forwarding for SMTP

Hello,

 

 

i have done port forwarding for SMTP traffic. for this I have configured VIP on port 25 and pool members of this VIP on port 2500.

 

 

however when i test i get this TWO below diff results.

 

 

1. ON DIRECT NODE :

 

$ telnet 10.155.63.126 2500

 

Trying 10.155.63.126...

 

Connected to A92SV00699JIV (10.155.63.126).

 

Escape character is '^]'.

 

220 localhost ESMTP SubEthaSMTP

 

HELO domain

 

250 localhost

 

QUIT

 

221 Bye

 

Connection closed by foreign host.

 

 

2. VIA VIP :

 

$ telnet 10.155.65.43 25

 

Trying 10.155.65.43...

 

Connected to uat.my.saint-gobain.com (10.155.65.43).

 

Escape character is '^]'.

 

-------------- here “220 localhost ESMTP SubEthaSMTP” is missing !!!!!!!!!!!!!!!!!!!

 

HELO domain

 

220 localhost ESMTP SubEthaSMTP

 

250 localhost

 

QUIT

 

-------------- here no reaction/resonse from the node

 

 

can anyone please help?
  • 2. VIA VIP :

    $ telnet 10.155.65.43 25

    Trying 10.155.65.43...

    Connected to uat.my.saint-gobain.com (10.155.65.43).

    Escape character is '^]'.

    -------------- here “220 localhost ESMTP SubEthaSMTP” is missing !!!!!!!!!!!!!!!!!!!

    HELO domain

    220 localhost ESMTP SubEthaSMTP

    250 localhost

    QUIT

    -------------- here no reaction/resonse from the node is 220 not a line below HELO domain??

    this is my testing.

    [root@ve10:Active] config  b virtual bar list
    virtual bar {
       snat automap
       pool foo
       destination 172.28.19.79:25
       ip protocol 6
    }
    
    [root@ve10:Active] config  telnet 172.28.19.79 25
    Trying 172.28.19.79...
    Connected to 172.28.19.79 (172.28.19.79).
    Escape character is '^]'.
    220 mail.f5.com ESMTP
    HELO me
    250 mail.f5.com
    QUIT
    221 mail.f5.com
    Connection closed by foreign host.
    
  • Hi Nitass

     

     

    if you see both outputs you can find difference in sequence.

     

     

    220 should be above HELO domain.

     

    after QUIT command 221 sequence of aborting is missing.
  • 220 should be above HELO domain. sorry i might misunderstand i.e. i thought you typed HELO too fast.

    e.g.

    [root@ve10:Active] config  telnet 172.28.19.79 25
    Trying 172.28.19.79...
    Connected to 172.28.19.79 (172.28.19.79).
    Escape character is '^]'.
    HELO me
    220 mail.f5.com ESMTP
    250 mail.f5.com
    

    anyway, if it is not, is there any special setting in the virtual server configuration?
  • This is the current setting I have on F5.

     

     

    [root@STG1F5LDB01:Active] config b virtual vs_jive_uat_25 list

     

    virtual vs_jive_uat_25 {

     

    snat automap

     

    pool pool_jive_uat_25

     

    destination 10.155.65.43:smtp

     

    ip protocol tcp

     

    profiles {

     

    http {}

     

    tcp {}

     

    }

     

    vlans INTERCO enable

     

    }

     

    [root@STG1F5LDB01:Active] config b pool pool_jive_uat_25 list

     

    pool pool_jive_uat_25 {

     

    members {

     

    10.155.63.126:rtsserv {

     

    priority 5

     

    }

     

    10.155.63.153:rtsserv {

     

    priority 1

     

    session user disabled

     

    }

     

    }

     

    }

     

  • why do you use http profile for smtp traffic? does it really work??
  • I tried removing HTTP profile.

     

     

    [root@STG1F5LDB01:Active] config b virtual vs_jive_uat_25 list

     

    virtual vs_jive_uat_25 {

     

    snat automap

     

    pool pool_jive_uat_25

     

    destination 10.155.65.43:smtp

     

    ip protocol tcp

     

    vlans INTERCO enable

     

    }

     

    [root@STG1F5LDB01:Active] config

     

     

    and after this, when i tested, connection drops immediately.

     

     

    Can you tell me tcpdump command to display capture during test? I want to test connection on VIP.

     

     

    i tried below and did not had anything in capture.

     

     

    [root@STG1F5LDB01:Active] config tcpdump -s0 dst 10.155.65.43 and dst port 25

     

    tcpdump: WARNING: eth0: no IPv4 address assigned

     

    tcpdump: verbose output suppressed, use -v or -vv for full protocol decode

     

    listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes

     

     

    0 packets captured

     

    10 packets received by filter

     

    0 packets dropped by kernel

     

  • Can you tell me tcpdump command to display capture during test? I want to test connection on VIP. can you try this?

     

     

    to screen

     

    tcpdump -nni 0.0 \(host 10.155.65.43 and port 25\) or \(host 10.155.63.126 or host 10.155.63.153 and port 2500\)

     

     

    to file

     

    tcpdump -nni 0.0:nnn -s0 -w /var/tmp/output.pcap \(host 10.155.65.43 and port 25\) or \(host 10.155.63.126 or host 10.155.63.153 and port 2500\)