[Samba] Packet Size 'Tuning'

[Andrew Mark]

Hi all,

I'm hoping someone has gone through the pain I'm going through in trying 
to 'tune' the packet size Samba uses such that we don't get packet 
overflow errors.

I'm getting these error when I perform: #> tcpdump -i ppp0 -n -n

12:08:48.376944 IP (tos 0x0, ttl 63, id 170, offset 0, flags [DF], proto 
TCP (6), length 1405)
     10.30.7.2.445 > 205.150.122.19.55639: Flags [.], cksum 0x4e9f 
(correct), seq 2733191:2734544, ack 13597, win 147, options [nop,nop,TS 
val 414105512 ecr 23936171], length 1353SMB-over-TCP packet:(raw data or 
continuation?)

12:08:48.376962 IP (tos 0x0, ttl 63, id 171, offset 0, flags [DF], proto 
TCP (6), length 1405)
     10.30.7.2.445 > 205.150.122.19.55639: Flags [.], cksum 0x2be8 
(correct), seq 2734544:2735897, ack 13597, win 147, options [nop,nop,TS 
val 414105512 ecr 23936171], length 1353SMB-over-TCP packet:(raw data or 
continuation?)

12:08:48.376981 IP (tos 0x0, ttl 63, id 172, offset 0, flags [DF], proto 
TCP (6), length 1405)
     10.30.7.2.445 > 205.150.122.19.55639: Flags [.], cksum 0xba2f 
(correct), seq 2735897:2737250, ack 13597, win 147, options [nop,nop,TS 
val 414105512 ecr 23936171], length 1353SMB-over-TCP packet:(raw data or 
continuation?)

12:08:48.376999 IP (tos 0x0, ttl 63, id 173, offset 0, flags [DF], proto 
TCP (6), length 1405)
     10.30.7.2.445 > 205.150.122.19.55639: Flags [.], cksum 0x0485 
(correct), seq 2737250:2738603, ack 13597, win 147, options [nop,nop,TS 
val 414105512 ecr 23936171], length 1353SMB-over-TCP packet:(raw data or 
continuation?)

my smb.conf is pretty plain:
[global]
     workgroup = IPM
     server string = Condo Fileserver
     netbios name = Condo

     interfaces = lo eth0 10.30.6.0/24 10.30.7.0/24 10.30.251.0/24 
205.150.122.0/24
     hosts allow = 127. 10.30.6. 10.30.7. 205.150.122. 10.30.251.

socket options = SO_RCVBUF=13504 SO_SNDBUF=13504
nt acl support = yes
inherit acls = yes
map acl inherit = yes
aio read size = 13472
aio write size = 13472


     # log files split per-machine:
     log file = /var/log/samba/%m.log
     # maximum size of 50KB per log file, then rotate:
     max log size = 50

     security = user
     passdb backend = tdbsam

     domain master = yes

     local master = yes
     os level = 66
     preferred master = yes

     wins support = yes
     dns proxy = yes

     load printers = yes
     cups options = raw

[homes]
     comment = Home Directories
     browseable = no
     writable = yes

[printers]
     comment = All Printers
     path = /var/spool/samba
     browseable = no
     guest ok = no
     writable = no
     printable = yes

[Quickbooks]
     comment = Everyone's QuickBooks
     path = /Shares/public/Quickbooks
     public = yes
     writable = yes
     printable = no
     read only = No
         guest ok = Yes
         force create mode = 0755
         force directory mode = 0777

[shared]
     comment = Shared Stuff
     path = /Shares/public
     public = yes
     writable = yes
     printable = no
     read only = No
         force create mode = 0777
         force directory mode = 0777
         guest ok = Yes

##end smb.conf ###

If I am correct, I'm transmitting a packet length of 1405 (kb?) but it's 
receiving a packet of 1353 (kb?)
My question is two-fold:
  - How do you read a tcpdump of Samba activity?
  - How to you tune the packet size that Samba uses?

Cheers,
  

Andrew Mark | Development Analyst | www.aimsystems.ca
local: 519-837-1072 | fax: 519-837-4063 | int'l 800-465-2961
12-350 Speedvale Ave. W. | Guelph, ON | N1H 7M7 | Canada


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