Forums & Blog

We have our mail server co-located at a datacenter.  One of our biggest expenses is bandwidth - we are billed on the 95th percentile - I would imagine that's pretty common.

Looking at our bandwidth spikes (those are what kill us), the SMTP traffic is one of the biggest offenders.  Can SmarterMail limit the Mb/sec so that we can flatten out those spikes?

We use CrashPlan (offsite backup) and it has that ability.  If SM could do this it would probably pay for itself in a matter of just a few months.

Any other thoughts on metering bandwidth?

 I will second that.  It would be a huge benefit to do this at the outgoing side of the server... I can't imagine any way to achieve this on the incoming side....

got me thinking though... would a better solution be to use a 3rd party traffic shaper to limit available bandwith by protocol?

SmarterMail 5.x enterprise does support throttling.  This can be set at domain or end users level.  You also have the chose to throttle by bandwidth or by number of messages.  When throttling is enable it will allow x amount of data per hours, after this limit is reached the email will be in the spool until the next hour is reached.  By using this you can set the max amount of traffic per hours that is sent from SmarterMail.

ST-BWard:

SmarterMail 5.x enterprise does support throttling.  This can be set at domain or end users level. 

I understand that, but I think the point is to;

1. limit the overall bandwidth by lowering it at the server level instead of per domain.  I'm assuming that throttling is cumulative with multiple domains. So If I set domain A to throttle at 1Mbps, and Domain B to throttle at 1Mbps, that's still a total of 2Mpbs when I want to throttle the entire server at 2Mpbs. Now multiple that out to 300+ domains and you have a throttling nightmare.

2. instead of stopping message delivery by delivering up to "X" and then resuming after time "Y", the ideal solution from the ISP level would be to reduce availalbe bandwidth/traffic to slow delivery instead of stopping it entirely.  This would have an overall impact of lowering all the ISP's bills that use the 95% billing rule common to data centers.  The server could be set to a maximum of X bandwidth available for all traffic on protocol X. 

I think what is being requested isn't Throttling. Throttling is designed to help stop/slow abusive users.  This is more of a "Bandwidth Shaping" feature request where the obejct isn't to stop or slow abbusive users but to limit the overall pipe alloted to specific protocols.

#2 really is the job of a traffic/packet shaper and not server software (allthough there are some Windows 2003 software based solutions on the market).  To do it on the server level you would have to have a layer in the App to handle TCP/UDP traffic patterns.  It would have a huge impact on cost savings for hosting firms since the one variable they have to pay for is thier monthly traffic/bandwidth.

Thanks
Robb

This, or something like it, may be worth a try:
http://www.softpedia.com/get/Network-Tools/Bandwidth-Tools/Bandwidth-Controller.shtml

cfwebmasters:

1. limit the overall bandwidth by lowering it at the server level instead of per domain.  I'm assuming that throttling is cumulative with multiple domains. So If I set domain A to throttle at 1Mbps, and Domain B to throttle at 1Mbps, that's still a total of 2Mpbs when I want to throttle the entire server at 2Mpbs. Now multiple that out to 300+ domains and you have a throttling nightmare.

Yes, exactly the problem I'm facing.

I'm sure we're only talking about *outgoing* traffic when we talk about throttling/shaping in SmarterMail.  Even the Free version of CrashPlan will do that:

http://www11.crashplan.com/consumer/features-specs.html#a_internet

We have a Juniper SSG firewall and I'm experimenting with its *incoming* traffic shaping.  Just scares me a little when it talks about "dropping packets" when the max bandwidth is reached.  Anyone have experience with hardware traffic shaping?

Duane

SonicWall Firewalls have a similar feature built in and it's a great way to prevent misuse of services and if a packet is dropped it is just resent.

We use the bandwidth management in SonicWall to reduce the overall incoming and outgoing bandwidth to 15MB. We then use other bandwidth management tools in SonicWall to restrict further the bandwidth by service for example:-

Website Port 80 and 443 are given up to 100% of the bandwidth and are guaranteed 60%
Mail Servers are given up to 25% of bandwidth and are guaranteed 10%
FTP is given up to 25% of bandwidth and are guaranteed 10%
Connections from our office are guaranteed 10% so if abuse takes place we can still manage services
etc.
etc.

This system works great as it not only prevents you going over your 95 percentile, but also limits abuse and allows you to prioritise  services and garantees that if abuse occurs on one service it would not affect others.

Thanks for the tip.  I was looking at much higher F5 Networks shaping boxes... I didn't even think to look at sonicwall firewalls - didn't realize they had dynamic bandwidth management in them.  There's only a price difference of about $20,000 :)

If you are in the UK I have a SonicWall Pro 3060 which cost around £2,000 only 18 months ago sat here doing nothing.

It has the Sonic Enhanced OS on it which costs around £500 extra compared to the basic Sonic OS and includes the bandwidth stuff I mentioned.

It's a very powerful firewall as it can handle up to 120,000 concurrent connections and 300Mbps stateful packet inspection.

The unit is boxed and in good condition with no scratches as I used it for just over a year in a data centre with very little work as the CPU didn't get pushed above 5% as it was used for protecting web servers.

If you are intersted in it send me a PM.

I played around with the SoftPerfect Bandwidth Manager a while back while working for an ISP. It didn't work very well as an Internet gateway (imagine that, a Windows based gateway didn't work well), but installed on the machine that needed its bandwidth shaped worked really well. It's cheap, easy to setup, and you can try it here.

http://www.softperfect.com/products/bandwidth/

For our 2 fiber Internet connections coming into the office, we use a firewall built with pfSense. It has good bandwidth shaping capabilities built into it, and since I built it out of a 3 GHz Core 2 Xeon with 2 GB RAM and 4 Intel gig server NICs, it works very nicely. It's been running for the last 325 days since I put it in without so much as a reboot. We have flat rate dedicated bandwidth, so we don't have to worry about anything like 95th percentile billing, but we do have to give priority to the 100 VPNs, etc...

http://www.pfsense.com/

I ended up enabling max bandwidth option in the firewall for both incoming and outgoing SMTP traffic.   Seems to be helping, no spikes lately.  I'll continue to watch it periodically and let you know if anything changes.

Duane

 Perhaps a better provider might also help. We offer our dedicated or co-located customers the ability to contract for burstable bandwidth billed at the 95th percentile with standard overage charges, and also fixed bandwidth options which can be specified on an inbound, outbound or both for traffic, and also selected ports. We throttle everything on our firewall clusters for our customers at no additional cost. If you want 2 Mbs total outbound traffic, that's all you will get. In your particular case you would contract for x Mbs for SMTP outbound traffic, not to exceed y Mbs. As part of your contract other bandwidth from your server could also be specified separately.  Over the years we found that forcing people into a position of not knowing what their operating costs are per month really pisses them off. Knowing what the bill is going to be every month makes our customers happy.  Talk to your provider. I would guess they would rather have a long term happy customer at a fixed price rather than a quick hit and an unhappy customer that will leave.

Of course our own SM servers run wide open but they offload their outbound mail to a cluster of gateway servers running Linux. At that point it's easy to use iptables to limit bandwidth inbound or outbound.

GA

Appreciate the advice - that is helpful.  We have 4Mb at the 95th percentile included and only pay for the overages - which is fine if we're getting that much traffic.  I just don't want to throw away money on SMTP which isn't as high priority as other traffic.

I still think SmarterMail would benefit from throttling at the application level.  I would guess most of their customers have no idea what their outgoing SMTP bandwidth spikes are costing them.  Probably very few limit SMTP traffic on their firewall.

An option in the SM interface is a whole lot more clear and easier to use than most firewalls.  Throttling both POP and outgoing SMTP together would be a huge score.  Would be a great feature advantage over Exchange and other competing mail servers.

Duane

you can also check out the bluecoat proxysg and packetshaper lines.