1811 & SMTP Issue

[plustechnology]

Hi all,

I have a client with a new 1811, and he's having a strange issue where some PC's experience SMTP time outs when sending mail.

After searching a bit, I read about the ip inspect settings which may have something to do with it, but the symptoms don't seem to match up:

1. Can send mail no problem from 2 machines.

2. Cannot send mail from the other 6 or so PC's (SMTP time outs).

3. On the problem PC's, he is unable to upload attachments to a webmail message (they're using webmail.registeredsite.com).

We're troubleshooting remotely and don't have free access to the unit so info may not be fast in coming, but I'll do my best.

Any ideas/suggestions?

Thanks,

Dave

[thisisshanky]

Can we take a look at the configs ?

Can you remove the inspect configs and see if this problem is clearing out ?

[Richard Burts]

If some PCs can use mail and some can not, it would be helpful to know something about the IP addressing on the PCs that can and the IP addressing of the PCs that can not (are the successful PCs in some range and the not successful in some slightly different range?).

When some machines do work and some do not I am inclined to look either for an access list somewhere along the path or for some routing issue.

As Sankar has asked, posting the configs would be a good place to start. I also ask for some information about the IP addressing of the PCs.

HTH

Rick

[plustechnology]

It turns out there is only one PC that works and it's the one that was the very first one to do SMTP after the router was configured. It is in the middle of the IP address range (192.168.1.122) with no special settings anywhere. This PC can also login to Hotmail, etc. while all the others cannot.

As far as the actual connections to the router, there is one switch connected to FE7 and a single PC at FE5. And of course the DSL is connected to FE1.

The Running Config is attached and any help you can provide would be greatly appreciated:

[Richard Burts]

David

I have looked at the config that you posted. While I do not yet have a good answer, I do have some things to check into. VLAN 1 has access-group 101 in. But there is not access list 101 in the posted config. So what is the story with access list 101? If it used to exist and was deleted, I have seen some situations where the router seems to remember the contents of deleted access lists. If the access list does exist please clarify its contents. If it no longer exists the please remove the access-group from the interface. To be really sure that we have eliminated this as a variable I might like to see the router rebooted.

HTH

Rick

[plustechnology]

Hi Rick,

Not sure why the access-list was in there. It's been removed, power cycled, and no change in behaviour.

Any ideas?

Cheers,

David

[Richard Burts]

David

Just to be sure - when you say access list has been removed, we mean that the ip access-group has been removed from the interface?

After re-reading your messages and re-looking at the config I do have a few questions and suggestions:

- can the problem PCs access outside resources? (can they browse the web to remote servers?)

- can the problem PCs access the mail server? (can they ping its IP address?)

- the original post mentions ip inspect but I do not see anything with ip inspect in the posted config. Am I not seeing something?

- the original post specifically mentions problems with attachments for mail. Is the problem specific to attachments or is it a problem with any kind of mail message? (with or without attachments?)

- I see the router is doing pppoe and it makes me wonder if there is a potential MTU issue. Is it possible that the PC that does work uses a smaller MSS or MTU than the other PCs? Perhaps one of the problem PCs could be configured for a smaller MTU and see if that makes any difference? (I have had some MTU issues and had good success using the ip tcp adjust-mss on the router to control MTU)

HTH

Rick